Программируемые логические контроллеры (ПЛК) и распределенные системы управления (РСУ)
Переход к Индустрии 4.0 требует сочетания богатого опыта в сфере промышленной автоматизации и успешной истории продвижения революционных технологий на рынок промышленного оборудования. ADI уже предоставляет универсальные решения в области средств ввода/вывода аналоговых сигналов, позволяющие вам создавать продукты, которые необходимы вашим клиентам уже сегодня для удовлетворения их требований в сфере производства и технологических процессов.
В то же время мы готовимся к завтрашнему дню. По мере распространения промышленных систем будет предъявляться еще больше требований к их возможностям, конфигурируемости и эффективности. ADI разрабатывает решения следующего поколения в области средств ввода/вывода аналоговых сигналов для удовлетворения потребностей этих систем, чтобы вы могли продолжать предоставлять то, что нужно вашим заказчикам.
Сигнальные цепочки
(5)
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Аналоговый модуль ввода для измерения температуры
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Аналоговый модуль ввода с групповой гальванической развязкой
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Аналоговый модуль ввода с межканальной гальванической развязкой
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Аналоговый модуль вывода с межканальной гальванической развязкой
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Аналоговый модуль вывода с групповой гальванической развязкой
Интерактивные сигнальные цепочки

Рекомендуемые продукты
AD5758

AD5758 - это одноканальный цифро-аналоговый преобразователь (ЦАП) с выходом тока и напряжения, который работает от напряжения питания в диапазоне от -33 В (минимум) на выводе AVSS до +33 В (максимум) на выводе AVDD1 при максимальной разнице между двумя напряжениями 60 В. Интегрированная схема динамического управления энергопотреблением минимизирует мощность, рассеиваемую корпусом, за счет регулировки напряжения питания (VDPC+), подаваемого на схему выходного драйвера VIOUT, в диапазоне от 5 В до 27 В при помощи понижающего импульсного преобразователя постоянного напряжения. Вывод CHART позволяет добавлять сигналы протокола HART® к выходному току.
Компонент имеет универсальный четырехпроводной последовательный интерфейс, который работает с частотой тактового сигнала до 50 МГц и совместим со стандартными интерфейсами SPI, QSPITM, MICROWIRETM, а также другими интерфейсами цифровых сигнальных процессоров и микроконтроллеров. Интерфейс также обеспечивает опциональную проверку на наличие ошибок в пакете при помощи циклического кода с избыточностью и имеет сторожевой таймер. По сравнению со своими предшественниками AD5758 имеет расширенные функции диагностики, включая схему мониторинга выходного тока и интегрированный 12-разрядный диагностический аналого-цифровой преобразователь (АЦП). Интеграция защитных ключей на выводах VIOUT, +VSENSE и −VSENSE повышает отказоустойчивость компонента. При совместном использовании с микросхемой управления питанием/изолятором ADP1031 компонент позволяет пользователям реализовать восьмиканальный модуль аналогового вывода с межканальной гальванической развязкой, имеющий рассеиваемую мощность менее 2 Вт и удовлетворяющий требованиям CISPR 11 Class B
Ключевые особенности продукта
- Динамическое управление энергопотреблением при помощи интегрированного понижающего преобразователя постоянного напряжения для уменьшения рассеиваемого тепла. При совместном использовании с микросхемой ADP1031 компонент позволяет реализовать восьмиканальный модуль аналогового вывода с межканальной гальванической развязкой, имеющий рассеиваемую мощность менее 2 Вт
- Ряд диагностических функций, включая интегрированный АЦП
- Высокая отказоустойчивость, защита выходных цепей от неправильного подключения (±38 В)
- Совместимость с протоколом HART
Области применения
- Управление технологическими процессами
- Управление приводами
- Модули аналогового вывода с гальванической развязкой каналов
- Программируемые логические контроллеры и распределенные системы управления
- Системы, работающие по протоколу HART
Applications
ADP1031

The ADP1031 is a high performance, isolated micropower management unit (PMU) that combines an isolated flyback dc-to-dc regulator, an inverting dc-to-dc regulator, and a buck dc-to-dc regulator, providing three isolated power rails. Additionally, the ADP1031 contains four, high speed, serial peripheral interface (SPI) isolation channels and three generalpurpose isolators for channel to channel applications where low power dissipation and small solution size is required.
Operating over an input voltage range of +4.5 V to +60 V, the ADP1031 generates isolated output voltages of +6 V to +28 V (adjustable version) or+ 21 V and +24 V (fixed versions) for VOUT1, factory programmable voltages of +5.15 V, +5.0 V, or +3.3 V for VOUT2, and an adjustable output voltages of −24 V to −5 V for VOUT3.
By default, the ADP1031 flyback regulator operates at a 250 kHz switching frequency and the buck and inverting regulators operate at 125 kHz. All three regulators are phase shifted relative to each other to reduce electromagnetic interference (EMI). The ADP1031 can be driven by an external oscillator in the range of 350 kHz to 750 kHz to ease noise filtering in sensitive applications.
The digital isolators integrated in the ADP1031 use Analog Devices, Inc., iCoupler® chip scale transformer technology, optimized for low power and low radiated emissions.
The ADP1031 is available in a 9 mm × 7 mm, 41-lead LFCSP and is rated for a −40°C to +125°C operating junction temperature range.
Applications
- Industrial automation and process control
- Instrumentation and data acquisition systems
- Data and power isolation
Applications
Технологии оснащения зданий
- Системы управления и автоматизации зданий
Промышленная автоматика
AD7124-4

AD7124-4 – это обладающий низким шумом и малым энергопотреблением, полностью интегрированный аналоговый входной интерфейс для задач прецизионного измерения. Компонент содержит 24-разрядный Σ-Δ аналого-цифровой преобразователь (АЦП) с низким шумом и может быть сконфигурирован для работы с 4 дифференциальными или 7 несииметричными/псевдодифференциальными входными сигналами. Интегрированный усилительный каскад с малым коэффициентом усиления позволяет подавать слабые сигналы непосредственно на АЦП.
Одно из основных преимуществ AD7124-4 заключается в том, что компонент дает пользователю возможность выбрать один из трех интегрированных режимов энергопотребления. Выбранный режим определяет потребляемый ток, диапазон скоростей обновления выходных данных и среднеквадратическое значение шума. Компонент также имеет несколько вариантов фильтрации, что позволяет пользователю получить максимальную степень свободы проектирования.
AD7124-4 способен поддерживать одновременное подавление помех на частотах 50 Гц и 60 Гц при работе с частотой обновления выходных данных 25 SPS (установление сигнала за один цикл). При понижении частоты обновления можно достичь подавления более 80 дБ.
AD7124-4 обеспечивает наивысшую степень интеграции сигнальной цепочки. Компонент содержит прецизионный, малощумящий источник опорного напряжения с малым дрейфом, а также поддерживает работу с внешним дифференциальным опорным напряжением, которое может быть буферизировано внутреннем буфером. К другим ключевым интегрированным блокам компонента относятся программируемые источники тока возбуждения с малым дрейфом, источники диагностических токов, а также генератор напряжения смещения, который устанавливает синфазное напряжение канала равным AVDD/2. Ключ цепи низкого напряжения питания позволяет пользователям отключать питание мостовых датчиков в интервалах между преобразованиями, гарантируя минимальную потребляемую системой мощность. Компонент также даёт пользователю возможность выбора между внутренним и внешним источником тактового сигнала.
Интегрированный блок управления последовательностью преобразования позволяет пользователю выбирать несколько каналов AD7124-4 для автоматического последовательного преобразования, упрощая обмен данными с компонентом. Одновременно может быть активно до 16 каналов, включая как каналы аналоговых входных сигналов, так и диагностические каналы, например, каналы контроля уровней напряжения питания или опорного напряжения. Эта уникальная особенность позволяет чередовать диагностику с преобразованиями сигналов внешних источников.
AD7124-4 поддерживает независимое конфигурирование каждого отдельного канала. Компонент позволяет реализовать до восьми конфигурационных настроек. Каждая конфигурация включает в себя опции коэффициента усиления, типа фильтра, частоты обновления выходных данных, буферизации и источника опорного напряжения. Пользователь может назначать любую из этих конфигураций любому из каналов в произвольном порядке.
AD7124-4 также обладает обширными возможностями функциональной диагностики, позволяющими повысить устойчивость решения. Они включают в себя проверку данных с использованием контрольной суммы (CRC), проверки сигнальной цепочки и проверки работоспособности последовательного интерфейса. Эти диагностические функции уменьшают число внешних компонентов, необходимых для реализации диагностики, сокращая требуемое пространство на печатной плате, время проектирования и стоимость. Значение доли безопасных отказов (SFF), показанное в тесте FMEDA (анализ видов, эффектов и диагностики отказов) типичного приложения, превышает 90% в соответствии с IEC 61508.
Компонент работает с однополярным напряжением питания аналоговой части в диапазоне от 2.7 В до 3.6 В или биполярным напряжением 1.8 В. Напряжение питания цифровой части имеет допустимый диапазон от 1.65 В до 3.6 В. Гарантированный рабочий температурный диапазон составляет от −40°C до +105°C. AD7124-4 выпускается в 32-выводном корпусе LFCSP и 24-выводном корпусе TSSOP.
Обратите внимание, что при ссылке на многофункциональные выводы, например, DOUT/RDY в техническом описании может указываться как полное имя вывода, так и только имя отдельной обсуждаемой функции, например, RDY.
Области применения
- Измерение температуры
- Измерение давления
- Управление промышленными процессами
- Измерительные приборы
- Интеллектуальные передатчики
Applications
AD7124-8

AD7124-8 - это обладающий низким шумом, малопотребляющий, полностью интегрированный аналоговый входной интерфейс для прецизионных измерений. Компонент включает в себя 24-разрядный Σ-Δ АЦП с низким шумом, который может быть сконфигурирован для работы с 8 дифференциальными входными сигналами или 15 несимметричными, либо псевдодифференциальными входными сигналами. Интегрированный каскад с малым коэффициентом усиления позволяет подавать сигналы непосредственно на АЦП.
Одним из основных достоинств AD7124-8 является возможность выбора пользователем одного из трех интегрированных режимов энергопотребления. Выбранный режим определяет уровень потребляемого тока, диапазон скоростей выходных данных и среднеквадратический уровень шума. Компонент также имеет ряд опций фильтрации, что дает пользователю максимальную степень свободы при проектировании.
AD7124-8 может обеспечивать одновременное подавление помех на частотах 50 Гц и 60 Гц при работе с частотой обновления выходных данных 25 SPS (установление сигнала за один такт); при меньших частотах выходных данных подавление может достигать более 80 дБ.
AD7124-8 обеспечивает наивысшую степень интеграции сигнального тракта. Компонент содержит прецизионный внутренний источник опорного напряжения с низким шумом и малым дрейфом на запрещенной зоне, а также поддерживает работу с внешним дифференциальным опорным напряжением, которое может буферизироваться внутренним буфером. К другим ключевым интегрированным функциям компонента относятся программируемые источники тока возбуждения с малым дрейфом, источники диагностических токов и генератор напряжения смещения, при помощи которого синфазное напряжение канала устанавливается равным AVDD/2. Ключ цепи низкого напряжения питания позволяет пользователю отключать мостовые датчики в интервалах между преобразованиями, гарантируя абсолютное минимальное потребление мощности системой. Компонент также позволяет пользователю выбирать между внутренним или внешним тактовом сигналом.
Интегрированный модуль управления последовательностью каналов позволяет пользователю выбирать несколько активных каналов, в которых AD7124-8 будет последовательно выполнять преобразования, упрощая взаимодействие с компонентом. Одновременно может быть активировано до 16 каналов, которыми могут быть как каналы аналоговых входных сигналов, так и диагностические каналы, например, канал проверки напряжения питания или опорного напряжения. Эта уникальная возможность позволяет чередовать диагностику с преобразованиями. AD7124-8 также поддерживает конфигурирование каналов в индивидуальном порядке. Компонент имеет восемь готовых конфигурационных настроек, каждая из которых задаёт определённую комбинацию коэффициента усиления, типа фильтра, частоты выходных данных, буферизации и источника опорного напряжения. Пользователь может назначить каналу любую из этих конфигураций в индивидуальном порядке.
AD7124-8 также имеет обширные возможности диагностики, включая проверку контрольной суммы (CRC), поверки сигнального тракта и проверки последовательного интерфейса, за счёт чего достигается повышенная надёжность решения. Эти диагностические функции сокращают количество внешних компонентов, необходимых для реализации диагностики, позволяя сэкономить пространство на печатной плате, ускорить проектирование и снизить стоимость. Для безопасных отказов в тестах FMEDA для типичного приложения составила более 90% в соответствии с IEC 61508.
Компонент работает с однополярным питанием аналоговой части в диапазоне от 2.7 В до 3.6 В или биполярным питанием 1.8 В. Напряжение питания цифровой части имеет допустимый диапазон от 1.65 В до 3.6 В. Рабочий температурный диапазон составляет от −40°C до +105°C. AD7124-8 выпускается в 32-выводном корпусе LFCSP.
Обратите внимание, что обозначение многофункциональных выводов в техническом описании, например, DOUT/RDY, может даваться либо целиком, либо только именем отдельной функции, обсуждаемой в конкретно взятом случае, например, RDY.
Области применения
- Измерение температуры
- Измерение давления
- Управление промышленными технологическими процессами
- Измерительные приборы
- Интеллектуальные передатчики
Applications
FIDO5100

The fido5100 and fido5200 (REM switch) are programmable IEEE 802.3 10 Mbps/100 Mbps Ethernet Internet Protocol Version 6 (IPv6) and Internet Protocol Version 4 (IPv4)switches that support virtually any Layer 2 or Layer 3 protocol. The switches are personalized to support the desired protocol by firmware that is downloaded from a host processor.
The firmware is contained in the real-time Ethernet multiprotocol (REM) switch driver and is downloaded at power-up. The REM switch can be ready for network data operation in less than 4 ms to support fast startup and quick connect type network functionality. The REM switch devices have the same signal assignments as defined in this data sheet.
The fido5100 supports the following protocols: PROFINET real time (RT) and isochronous real time (IRT), EtherNet/IP with and without device level ring (DLR), Modbus TCP, and POWERLINK.
The fido5200 supports the following protocols: EtherCAT and all protocols defined for the fido5100.
The REM switch is intended for use with a host processor. Network operation is handled using the functions and services provided in the REM switch driver. The host processor can implement any protocol stack by integrating it with the REM switch driver. An example application is shown in Figure 11.
The REM switches are available in a 144-ball chip scale package ball grid array (CSP_BGA) package.
Note that throughout this data sheet, multifunction pins, such as A02/ALE, are referred to either by the entire pin name or by a single function of the pin, for example, ALE, when only that function is relevant.
Applications
- Industrial automation
- Process control
- Managed Ethernet switch
Applications
Промышленная автоматика
- Программируемые логические контроллеры (ПЛК) и распределенные системы управления (РСУ)
FIDO5200

The fido5100 and fido5200 (REM switch) are programmable IEEE 802.3 10 Mbps/100 Mbps Ethernet Internet Protocol Version 6 (IPv6) and Internet Protocol Version 4 (IPv4)switches that support virtually any Layer 2 or Layer 3 protocol. The switches are personalized to support the desired protocol by firmware that is downloaded from a host processor.
The firmware is contained in the real-time Ethernet multiprotocol (REM) switch driver and is downloaded at power-up. The REM switch can be ready for network data operation in less than 4 ms to support fast startup and quick connect type network functionality. The REM switch devices have the same signal assignments as defined in this data sheet.
The fido5100 supports the following protocols: PROFINET real time (RT) and isochronous real time (IRT), EtherNet/IP with and without device level ring (DLR), Modbus TCP, and POWERLINK.
The fido5200 supports the following protocols: EtherCAT and all protocols defined for the fido5100.
The REM switch is intended for use with a host processor. Network operation is handled using the functions and services provided in the REM switch driver. The host processor can implement any protocol stack by integrating it with the REM switch driver. An example application is shown in Figure 11.
The REM switches are available in a 144-ball chip scale package ball grid array (CSP_BGA) package.
Note that throughout this data sheet, multifunction pins, such as A02/ALE, are referred to either by the entire pin name or by a single function of the pin, for example, ALE, when only that function is relevant.
Applications
- Industrial automation
- Process control
- Managed Ethernet switch
Applications
Промышленная автоматика
- Программируемые логические контроллеры (ПЛК) и распределенные системы управления (РСУ)
Примеры типовых проектов
CN0203

Применяемые компоненты
Applications
CN0225

The circuit, shown in Figure 1, is a complete analog front end
for digitizing ±10 V industrial level signals with a 16-bit
differential input PulSAR® ADC. The circuit provides a high
impedance instrumentation amplifier input with high CMR,
level shifting, attenuation, and differential conversion, with only
two analog components. Because of the high level of integration,
the circuit saves printed circuit board space and offers a cost
effective solution for a popular industrial application.
Signal levels of up to ±10 V are typical in process control and industrial automation systems. With smaller signal inputs from sensors such as thermocouples and load cells, large commonmode voltage swings are often encountered. This requires a flexible analog input that handles both large and small differential signals with high common-mode rejection and also has a high impedance input.
Figure 1. High Performance Analog Front for Industrial Process Control (Simplified Schematic: All Connections and Decoupling Not Shown)
Attenuation and level shifting are necessary to process
industrial level signals with modern low voltage ADCs. In
addition, fully differential input ADCs offer the advantages of
good common-mode rejection, reduction in second-order
distortion products, and simplified dc trim algorithms.
Industrial signals, therefore, need further conditioning to
properly interface with differential input ADCs.
The circuit in Figure 1 is a complete and highly integrated analog front end industrial level signal conditioner that uses only two active components to drive an AD7687 differential input 16-bit PulSAR ADC: the AD8295 precision in-amp (with two on-chip auxiliary op amps) and the AD8275 level translator/ADC driver. An ADR431 low noise 2.5V XFET® reference supplies the voltage reference for the ADC.
The AD8295 is a precision instrumentation amplifier with two
uncommitted on-chip signal processing amplifiers and two
precisely matched 20 kΩ resistors in a small 4 mm × 4 mm
package.
The AD8275 is a G = 0.2 difference amplifier that can be used to
attenuate ±10 V industrial signals, and the attenuated signal can
be easily interfaced to a single supply low voltage ADC. The
AD8275 performs the attenuation and level shifting function in
the circuit, maintaining good CMR without any need for
external components.
The AD7687 is a 16-bit, successive approximation ADC that operates from a single power supply between 2.3 V and 5.5 V. It has a differential input for good CMR and also offers the ease of use associated with SAR ADCs.
Применяемые компоненты
ADR431
Ultralow Noise XFET® Voltage References with Current Sink and Source Capability
AD8295
Прецизионный инструментальный усилитель с дополнительными усилителями обработки сигнала
AD8275
Драйвер 16-разрядных АЦП с преобразованием уровня сигнала, G = 0.2
AD7687
16-разрядный АЦП PulSAR® с дифференциальным входом в корпусе MSOP/QFN, INL 1.5 LSB, быстродействие 250 kSPS
Applications
CN0337

The circuit shown in Figure 1 is a completely isolated 12-bit, 300 kSPS RTD temperature measuring system that uses only three active devices. The system processes the output of a Pt100 RTD and includes an innovative circuit for lead-wire compensation using a standard 3-wire connection. The circuit operates on a single 3.3 V supply. The total error after room temperature calibration is less than ±0.24% FSR for a ±10°C change in temperature, making it ideal for a wide variety of industrial temperature measurements.
The small footprint of the circuit makes this combination an industry-leading solution for temperature measurements where accuracy, cost, and size play a critical role. Both data and power are isolated, thereby making the circuit robust to high voltages and also ground-loop interference often encountered in harsh industrial environments.
The novel circuit for 3-wire RTD lead wire compensation was developed by Hristo Ivanov Gigov, Associate Professor and PhD, and Stanimir Krasimirov Stankov, Engineer and PhD Student, Department of Electronic Engineering and Microelectronics, Technical University of Varna, Varna, Bulgaria.

Figure 1. Resistance Deviation to Digital Conversion with Isolation Using Pt100 RTD Sensor (All Connections and Decoupling Not Shown)
Применяемые компоненты
ADUM5401
Quad-Channel, 2.5 kV Isolators with Integrated DC-to-DC Converter (3/1 channel directionality)
AD7091R
Малопотребляющий 12-разрядный АЦП с интегрированным источником опорного напряжения в 10-выводных корпусах LFCSP и MSOP, быстродействие 1 MSPS
AD8608
Low Noise, CMOS, Rail-to-Rail, Input/Output Precision Quad Op Amp
Applications
CN0198

The circuit shown in Figure 1 provides a unique power saving solution for a digital-to-analog converter (DAC)-based, 4 mA to 20 mA output circuit. To provide sufficient headroom for typical resistive loads between 10 Ω and 1000 Ω, traditional 4 mA to 20 mA output driver stages must operate on at least 20 V (plus some additional headroom) to provide a sufficient voltage to drive high value resistive loads. For low value resistive loads, however, the fixed value, high voltage supply results in significant internal power dissipation that can affect DAC accuracy and require additional heat sinking.
The AD5755 quad 16-bit DAC has four independent high efficiency, internal dc-to-dc converters that drive the four output stages at a dynamically adjusted boost voltage based on sensing the actual output voltage of the 4 mA to 20 mA driver. The boost circuit maintains several volts of headroom on the output stage, regardless of the load resistance, thereby reducing the maximum internal power dissipation by a factor of approximately 4× for a 24 mA output current into a 10 Ω load.
The internal dc-to-dc converters require an external 5 V supply and can draw significant currents when the DAC outputs full-scale slew. A high efficiency external dc-to-dc converter circuit based on the ADP2300 is driven from the 15 V and supplies this voltage. The ADP2300 has excellent transient response to large current steps up to 800 mA and ensures proper operation of the boost converters as well as eliminating the need for a separate 5 V supply.
The entire circuit operates on ±15 V supplies that allow the DAC to provide voltage outputs that cover the industrial signal level range of up to ±10 V in addition to the 4 mA to 20 mA outputs. This combination of parts is a low cost, power efficient solution that minimizes the number of external components required and that ensures 16-bit performance for varying load conditions.

Figure 1. Current and Voltage Output DAC with Modified Power Scheme (Simplified Schematic: All Connections and Decoupling Not Shown)
Применяемые компоненты
Applications
CN0321

The AD5422 16-bit digital-to-analog converter (DAC) is software configurable and provides all the necessary current and voltage outputs.
The AD5700-1, the industry’s lowest power and smallest footprint HART-compliant IC modem, is used in conjunction with the AD5422 to form a complete HART-compatible 4 mA to 20 mA solution. The AD5700-1 includes a precision internal oscillator that provides additional space savings, especially in channel-to-channel isolated applications.
PLC/DCS solutions must be isolated from the local system controller to protect against ground loops and to ensure robustness against external events. Traditional solutions use discrete ICs for both power and digital isolation. When multichannel isolation is needed, the cost and space of providing discrete power solutions becomes a big disadvantage. Solutions based on optoisolators typically have reasonable output regulation but require additional external components, thereby increasing board area. Power modules are often bulky and can provide poor output regulation. The circuit in Figure 1 uses the ADuM347x family of isolators and power regulation circuitry along with associated feedback isolation. External transformers are used to transfer power across the isolation barrier.
The ADuM3482 provides the UART signal isolation for the AD5700-1.
The ADP2441, 36 V step-down dc-to-dc regulator, accepts an industrial standard 24 V supply, with wide tolerance on the input voltage. It steps this down to 5 V to power all controller side circuitry. The circuit also includes standard external protection on the 24 V supply terminals, as well as protection against dc overvoltage of +36 V down to −28 V.
1 HART is a registered trademark of the HART Communication Foundation.

Figure 1. Functional Block Diagram (Simplified Schematic: All Connections and Decoupling Not Shown)
Применяемые компоненты
AD5422
Single Channel, 16-Bit, Current Source & Voltage Output DAC, HART Connectivity
ADP2441
Синхронный понижающий стабилизатор постоянного напряжения, 36 В/1 А
ADUM3471
Isolated Switching Regulators (3/1 Channel Directionality)
AD5700-1
Малопотребляющий HART модем с прецизионным внутренним генератором
ADUM3482
Small, 3.75 kV RMS Quad Digital Isolators (2/2 Channel Directionality)
Applications
CN0233

The circuit uses digital isolation, as well as PWM-controlled power regulation circuitry along with associated feedback isolation. External transformers are used to transfer power across the isolation barrier, and the entire circuit operates on a single +5 V supply located on the primary side. This solution is superior to isolated power modules, which are often bulky and may provide poor output regulation.
Digital isolators are superior to opto-isolators especially when multichannel isolation is needed. The integrated design isolates the circuit from the local system controller to protect against ground loops and also to ensure robustness against external events often encountered in harsh industrial environments.
Figure 1. Isolated 16-Bit Current and Voltage Output DAC with Isolated Power Supplies
Применяемые компоненты
Applications
CN0270

The circuit shown in Figure 1 uses the AD5700, the industry’s lowest power and smallest footprint HART1-compliant IC modem and the AD5420, a 16-bit current-output DAC, to form a complete HART-compatible 4 mA to 20 mA solution.
For additional space savings, the AD5700-1 offers a 0.5% precision internal oscillator.

This circuit adheres to the HART physical layer specifications as defined by the HART Communication Foundation, for example, the analog rate of change and noise during silence specifications.
For many years, 4 mA to 20 mA communication has been used in process control instrumentation. This communication method is reliable and robust, and offers high immunity to environmental interference over long communication distances. A limitation, however, is that only 1-way communication of one process variable at a time is possible.
The development of the highway addressable remote transducer (HART) standard provided highly capable 2-way digital communication, simultaneously with the 4 mA to 20 mA analog signaling used by traditional instrumentation equipment. This allows for features such as remote calibration, fault interrogation, and transmission of additional process variables. Put simply, HART is a digital two-way communication in which a 1 mA peak-to-peak frequency-shift-keyed (FSK) signal is modulated on top of the 4 mA to 20 mA analog current signal.
Применяемые компоненты
Applications
CN0229

An ultralow drift (2 ppm/°C typical), 2.5 V voltage reference with high drive capability (up to ±5 mA) is integrated in the AD5686R and provides the reference voltage for both the AD5686R and the AD5750-2. This guarantees low noise, high accuracy, and low temperature drift for the circuit.
The ADuM1301 and ADuM5400 provide 2500 V rms isolation both on power, and all the necessary signals between the analog signal chain and the host controller.
For multichannel I/O card applications that need more than 4 channels, several AD5686Rs can be connected in a daisy chain, and no additional external digital I/O circuits are required. This minimizes the cost, especially for high channel count isolated applications.
The circuit also contains key features for industrial applications, such as on-chip output fault detection, packet error checking (PEC) by the CRC, flexible power-up options, and ESD protection (4 kV for the AD5686R, human body model and 3 kV for the AD5750-2, human body model), making it an ideal choice for robust industrial control systems. No external precision resistors or calibration routines are needed to maintain consistent performance in mass production, thereby making it ideal for PLC or DCS modules.
Figure 1. Simplified Schematic of the Analog Output Circuit (All Connections and Protection Circuits Not Shown)
Применяемые компоненты
ADUM1301
Triple-Channel Digital Isolator
ADUM5400
Quad-Channel Isolator with Integrated DC-to-DC Converter (4/0 channel directionality)
AD5686R
Quad, 16-Bit nanoDAC+™ with 2 ppm/°C On-Chip Reference and SPI Interface
AD5685R
Quad, 14-Bit nanoDAC+ with 2 ppm/°C On-Chip Reference and SPI Interface
AD5684R
Quad, 12-Bit nanoDAC+ with 2 ppm/°C On-Chip Reference and SPI Interface
AD5750-2
Промышленные выходные драйверы по току и напряжению и программируемым выходным диапазоном
AD5686
Quad, 16-Bit nanoDAC+ with SPI Interface
AD5684
Quad, 12-Bit nanoDAC+ with SPI Interface
AD5683R
Миниатюрный 16-разрядный ЦАП nanoDAC+ с интерфейсом SPI, INL ±2 (16 бит) LSB и внешним источником опорного напряжения
AD5682R
Миниатюрный 16-разрядный ЦАП nanoDAC+ с интерфейсом SPI, INL ±2 (16 бит) LSB и внешним источником опорного напряжения
AD5681R
Миниатюрный 16-разрядный ЦАП nanoDAC+ с интерфейсом SPI, INL ±2 (16 бит) LSB и внешним источником опорного напряжения
AD5683
Миниатюрный 16-разрядный ЦАП nanoDAC+ с интерфейсом SPI, INL ±2 (16 бит) LSB и внешним источником опорного напряжения
AD5676R
Восьмиканальный 16-разрядный ЦАП nanoDAC+ с интерфейсом SPI и источником опорного напряжения, дрейф 2 ppm/°C
AD5672R
Восьмиканальный 12-разрядный ЦАП nanoDAC+ с интерфейсом SPI и источником опорного напряжения, дрейф 2 ppm/°C
AD5592R
8 Channel, 12-Bit, Configurable ADC/DAC with on-chip Reference, SPI interface
AD5593R
8-Channel, 12-Bit, Configurable ADC/DAC with On-Chip Reference, I2C Interface
Applications
CN0295

The circuit shown in Figure 1 is a flexible current transmitter that converts the differential voltage output from a pressure sensor to a 4 mA-to-20 mA current output.
The circuit is optimized for a wide variety of bridge-based voltage or current driven pressure sensors, utilizes only five active devices, and has a total unadjusted error of less than 1%. The power supply voltage can range from 7 V to 36 V depending on the component and sensor driver configuration.
The input of the circuit is protected for ESD and voltages beyond the supply rail, making it ideal for industrial applications.

Применяемые компоненты
Applications
CN0287

The circuit shown in Figure 1 is a completely isolated 4-channel temperature measurement circuit optimized for performance, input flexibility, robustness, and low cost. It supports all types of thermocouples with cold junction compensation and any type of RTD (resistance temperature detector) with resistances up to 4 kΩ for 2-, 3-, or 4-wire connection configurations.
The RTD excitation current are is programmable for optimum noise and linearity performance.
RTD measurements achieve 0.1°C accuracy (typical), and Type-K thermocouple measurements achieve 0.05°C typical accuracy because of the 16-bit ADT7310 digital temperature sensor used for cold-junction compensation. The circuit uses a four-channel AD7193 24-bit sigma-delta ADC with on-chip PGA for high accuracy and low noise.
Input transient and overvoltage protection are provided by low leakage transient voltage supressors (TVS) and Schottky diodes. The SPI-compatible digital inputs and outputs are isolated (2500 V rms), and the circuit is operated on a fully isolated power supply.

Figure 1. 4-Channel Thermocouple and RTD Circuit (Simplified Schematic: All Connections and Decoupling Not Shown)
Применяемые компоненты
AD8603
MicroPower RRIO Low Noise Precision Single CMOS Op Amp
ADUM5401
Quad-Channel, 2.5 kV Isolators with Integrated DC-to-DC Converter (3/1 channel directionality)
ADT7310
16-разрядный цифровой датчик температуры с интерфейсом SPI, погрешность ±0.5°C
AD7193
Четырехканальный 24-разрядный сигма-дельта АЦП с крайне низким шумом и программируемый усилитель, частота выходных данных 4.8 кГц
ADR3440
Микропотребляющий прецизионный источник опорного напряжения 4.096 В
ADUM1280
3kV rms, Default High, Dual-Channel Digital Isolators (2/0 Channel Directionality)
ADG738
CMOS, Low Voltage, 3-Wire, Serially Controlled, Matrix Switch
AD5201
33-Position Digital Potentiometer
ADG702
CMOS Low Voltage 2 Ω SPST Switch
Applications
CN0278

The circuit shown in Figure 1 uses the AD5700, the industry’s lowest power and smallest footprint HART®1-compliant IC modem, and the AD5422, a 16-bit current output and voltage output DAC, to form a complete HART-compatible 4 mA to 20 mA solution. The use of the OP184 in the circuit allows the IOUT and VOUT pins to be shorted together, thus reducing the number of screw connections required in programmable logic control (PLC) module applications. For additional space savings, the AD5700-1 offers a 0.5% precision internal oscillator.

Application Note AN-1065 describes a manner in which the AD5420 IOUT DAC can be configured for HART communication compliance. AN-1065 outlines how the AD5700 HART modem output can be attenuated and ac coupled into the AD5420 via the CAP2 pin. The same is true of the AD5422. However, if the application involves a particularly harsh environment, an alternative circuit configuration can be used which offers better power supply rejection characteristics. This alternative circuit requires the use of the external RSET resistor and involves coupling the HART signal into the RSET pin of the AD5420 or AD5422. The CN-0270 describes this solution for the AD5420, typical of line-powered transmitter applications. The current circuit note is relevant to the AD5422, which, unlike the AD5420, offers both a voltage and a current output pin, and so is particularly useful in PLC/distributed control system (DCS) applications. The AD5422 is available in both 40-lead LFCSP and 24-lead TSSOP packages and the relevance of this, to the circuit characteristics, is examined in the Circuit Description section.
This circuit adheres to the HART physical layer specifications as defined by the HART Communication Foundation, for example, the output noise during silence and the analog rate of change specifications.
For many years, 4 mA to 20 mA communication has been used in process control instrumentation. This communication method is reliable and robust, and offers high immunity to environmental interference over long communication distances. A limitation, however, is that only 1-way communication of one process variable at a time is possible.
The development of the highway addressable remote transducer (HART) standard provided highly capable 2-way digital communication, simultaneously with the 4 mA to 20 mA analog signaling used by traditional instrumentation equipment. This allows for features such as remote calibration, fault interrogation, and transmission of additional process variables. Put simply, HART is a digital two-way communication in which a 1 mA peak-to-peak, frequency-shift-keyed (FSK) signal is modulated on top of the 4 mA to 20 mA analog current signal.
Применяемые компоненты
OP184
Rail-to-Rail операционный усилитель с однополярным питанием
AD5420
Single-Channel, 16-Bit, Serial Input, 4 mA to 20 mA, Current Source DAC, HART Connectivity
AD5422
Single Channel, 16-Bit, Current Source & Voltage Output DAC, HART Connectivity
AD5421
16-разрядный ЦАП с выходом тока 4-20 мА, последовательным входом и питанием от токовой петли
AD5700
Малопотребляющий HART модем
AD5700-1
Малопотребляющий HART модем с прецизионным внутренним генератором
Applications
CN0335

The circuit shown in Figure 1 is a completely isolated 12-bit, 300 kSPS data acquisition system utilizing only three active devices.
The system processes ±10 V input signals using a single 3.3 V supply. The total error after room temperature calibration is less than ±0.1% FSR over a ±10°C temperature change, making it ideal for a wide variety of industrial measurements.
The small footprint of the circuit makes this combination an industry-leading solution for data acquisition systems where the accuracy, speed, cost, and size play a critical role. Both data and power are isolated, thereby making the circuit robust to high voltages and also ground-loop interference often encountered in harsh industrial environments.

Figure 1. ±10 V Single Supply Data Acquisition System with Isolation (All Connections and Decoupling Not Shown)
Применяемые компоненты
AD8606
Precision, Low Noise, RRIO, CMOS Op Amp (Dual)
ADUM5401
Quad-Channel, 2.5 kV Isolators with Integrated DC-to-DC Converter (3/1 channel directionality)
AD7091R
Малопотребляющий 12-разрядный АЦП с интегрированным источником опорного напряжения в 10-выводных корпусах LFCSP и MSOP, быстродействие 1 MSPS
Applications
CN0348

The circuit in Figure 1 is a complete single-supply,16-bit buffered voltage output DAC that maintains ±1 LSB integral and differential nonlinearity by utilizing a CMOS DAC followed by an innovative amplifier that has no crossover distortion.
The circuit eliminates the crossover nonlinearity associated with most rail-to-rail op amps that can be as high as 4 or 5 LSBs for a 16-bit system.
This industry-leading solution is ideal for industrial process control and instrumentation applications where a compact, single-supply, low cost, and highly linear 16-bit buffered voltage source is required.
Total power dissipation for the three active devices is less than 25 mW typical when operating on a single 6 V supply.

Figure 1. ±1 LSB Linear 16-Bit Buffered Voltage Output DAC (Simplified Schematic, All Connections and Decoupling Not Shown)
Применяемые компоненты
Applications
CN0336

The system processes 4 mA to 20 mA input signals using a single 3.3 V supply. The total error after room temperature calibration is ±0.06% FSR over a ±10°C temperature change, making it ideal for a wide variety of industrial measurements.
The small footprint of the circuit makes this combination an industry-leading solution for 4 mA to 20 mA data acquisition systems where the accuracy, speed, cost, and size play a critical role. Both data and power are isolated, thereby making the circuit robust to high voltages and also ground-loop interference often encountered in harsh industrial environments.

Figure 1. 4 mA to 20 mA Single Supply Analog to Digital Conversion with Isolation (All Connections and Decoupling Not Shown)
Применяемые компоненты
AD8606
Precision, Low Noise, RRIO, CMOS Op Amp (Dual)
ADUM5401
Quad-Channel, 2.5 kV Isolators with Integrated DC-to-DC Converter (3/1 channel directionality)
AD7091R
Малопотребляющий 12-разрядный АЦП с интегрированным источником опорного напряжения в 10-выводных корпусах LFCSP и MSOP, быстродействие 1 MSPS
Applications
CN0364

The analog input circuit is designed for group isolated industrial analog inputs and can support voltage and current input ranges including ±5 V, ±10 V, 0 V to +5 V, 0 V to +10 V, +4 mA to +20 mA, and 0 mA to +20 mA.
The circuit is powered from a standard 24 V bus supply and generates an isolated 5 V system supply voltage.
Применяемые компоненты
AD5700-1
Малопотребляющий HART модем с прецизионным внутренним генератором
AD7173-8
Малопотребляющий, 8-/16-канальный, 24-разрядный сигма-дельта АЦП с высокой степенью интеграции, быстродействие 31.25 kSPS
ADG704
CMOS, Low Voltage 2.5 Ω 4-Channel Multiplexer
ADP2441
Синхронный понижающий стабилизатор постоянного напряжения, 36 В/1 А
ADUM3151
3.75 kV, 7-Channel, SPIsolator Digital Isolators for SPI (with 2/1 Aux channel directionality)
ADUM5211
Dual-Channel Isolators with Integrated DC-to-DC Converter (1/1 Channel Directionality)
AD7176-2
24-разрядный сигма-дельта АЦП с быстродействием 250 kSPS и временем установления 20 мкс
AD7173-8
Малопотребляющий, 8-/16-канальный, 24-разрядный сигма-дельта АЦП с высокой степенью интеграции, быстродействие 31.25 kSPS
AD7175-2
24-разрядный сигма-дельта АЦП с Rail-to-Rail буферами, быстродействием 250 kSPS и временем установления 20 мкс
AD7172-2
Малопотребляющий 24-разрядный сигма-дельта АЦП с Rail-to-Rail буферами, быстродействие 31.25 KSPS
AD7177-2
32-разрядный сигма-дельта АЦП с быстродействием 10 kSPS, временем установления 100 мкс и Rail-to-Rail буферами
AD7172-4
Малопотребляющий 4-/8-канальный, 24-разрядный сигма-дельта АЦП с Rail-to-Rail буферами, быстродействие 31.25 kSPS
Applications
CN0148

In measurement and protection systems, simultaneous sampling capability is needed to maintain the phase information between the current and voltage channels on multiphase power line networks. The wide dynamic range capability of the AD7606 makes it ideal for capturing both under voltage/current and over voltage/current conditions. The input voltage range is pin-programmable for either ±5 V or ±10 V.
This circuit note describes details of the recommended PC board layout for applications using multiple AD7606 devices. The layout is optimized for channel-to-channel matching and part-to-part matching and will help reduce the complexity of calibration routines in high channel count systems. The circuit provides the ability to use the AD7606 2.5 V internal reference when channel-to-channel matching is important or an external ADR421 precision high accuracy (B grade: ±1 mV max), low drift (B grade: 3 ppm/°C max), low noise (1.75 μV p-p, typical, 0.1 Hz to 10 Hz) reference for high channel applications that require excellent absolute accuracy. The low noise and the stability and accuracy characteristics of the ADR421 make it ideal for high precision conversion applications. The combination of the two devices yields a level of integration, channel density, and accuracy that is unsurpassed in the industry.
Применяемые компоненты
ADR421
Ultraprecision, Low Noise, 2.500 V XFET® Voltage References
AD7606
8-канальная система обработки сигналов с 16-битным биполярным АЦП одновременной выборки
AD7606-4
4-канальная система обработки сигналов с 16-разрядным, биполярным АЦП одновременной выборки
AD7606-6
16-битная 6-канальная система аналогово-цифровой обработки данных одновременной выборки
AD7605-4
Четырехканальная система сбора данных с 16-разрядным АЦП одновременной выборки с биполярным входным напряжением
Applications
CN0143

With single-ended signaling, one wire from the signal source is routed throughout the system to the data acquisition interface. The voltage measured is the difference between the signal and the ground. Unfortunately, “ground” can be a different level in different places because the ground impedance can never be zero. This can lead to errors when using single-ended inputs, especially where the signal trace is long and grounds currents contain large digital transients. Single-ended signal runs are sensitive to noise pickup because they act as an antenna, picking up electrical activity. With single-ended inputs there is no way of distinguishing between the signal and the interfering noise. Most of the ground and noise problems are solved by differential signaling.
With differential signaling, two signal wires run from the signal source to the data acquisition interface. This can solve both of the problems caused by single-ended connections. Noise between the sending and receiving ground planes acts as a common-mode signal and is, therefore, greatly attenuated. The use of twisted pair wire causes noise pickup to appear as a common-mode signal, which is also greatly attenuated at the receiver. Another advantage of differential transmission is that the differential signal has twice the amplitude of the equivalent single-ended signal, therefore giving greater noise immunity.
Here we describe a differential driver that can be adapted to either a voltage or current output DAC. The driver is based on the dual AD8042 op amp configured as a cross-coupled differential driver. The AD8042 has a rail-to-rail output stage that operates within 30 mV of either rail and an input stage that can operate 200 mV below the negative supply (ground in this circuit) and within 1 V of the positive supply. In addition, the AD8042 has 160 MHz bandwidth and fast settling time, making it an ideal choice for the output driver.
The voltage output DAC is the 12-bit AD5620, a member of the nanoDAC® family. The DAC contains an on-chip 5 ppm/°C reference and is available in an 8-lead SOT-23 or MSOP package. The current output DAC is the 12-bit AD5443, which is available in a 10-lead MSOP package.
The two circuits represent a cost effective, low power, and small board area solution for generating differential signals from industrial CMOS DACs. Both circuits operate on a single +5 V supply.

Применяемые компоненты
Applications
CN0146

This circuit provides a programmable gain function using a quad SPST switch (ADG1611) and a resistor-programmable instrumen-tation amplifier (AD620).
The gain values are set by controlling the external gain setting resistor value, RG, with the four SPST switches, which are connected to four precision resistors.
Low switch on resistance is critical in this application, and the ADG1611 has the industry’s lowest RON (1 Ω typical) and is available in the smallest package, a 16-lead, 4 mm × 4 mm LFCSP.
The combination of the industry-standard low cost AD620 and the ADG1611 quad switch yields unmatched performance in this circuit and provides all the benefits of a precision instrumentation amplifier, along with the programmable gain feature.
Применяемые компоненты
Applications
CN0169

Achieving true 16-bit performance with a voltage output DAC requires selecting not only the correct DAC but also the correct complementary supporting components. This circuit provides a low risk solution for precision 16-bit digital-to-analog conversion using the AD5542A/AD5541A voltage output DAC with the ADR421 voltage reference and the AD8675 ultralow offset op amp used as the voltage reference buffer.
The reference buffer is critical to the design because the input impedance at the DAC reference input is heavily code- dependent and will lead to linearity errors if the DAC reference is not adequately buffered. With a high open-loop gain of 120 dB, the AD8675 has been proven and tested to meet the settling time, offset voltage, and low impedance drive capability required by this circuit application.
The precision, low offset OP1177 can be used as an optional output buffer if needed.
This combination of parts provides industry-leading 16-bit integral nonlinearity (INL) of ±1 LSB and differential nonlinearity (DNL) of ±1 LSB with guaranteed monotonicity, as well as low power, small PCB area, and cost effectiveness.

Применяемые компоненты
AD8675
Прецизионный ОУ с Rail-to-Rail выходом, шумом 2.8 нВ/√Гц и питанием 36 В
ADR421
Ultraprecision, Low Noise, 2.500 V XFET® Voltage References
OP1177
Прецизионный одноканальный ОУ с низким шумом и малым входным током смещения
AD5541A
2.7 V to 5.5 V, Serial-Input, Voltage-Output, 16-/12-Bit nanoDAC in 8-lead 3 mm × 3 mm LFCSP
AD5542A
16-разрядный ЦАП nanoDAC™ с последовательным входом, выходом напряжения, напряжением питания 2.7 – 5.5 В в 10-выводном корпусе LFCSP или 16-выводных корпусах LFCSP (3 мм x 3 мм) и TSSOP
Applications
CN0206

The circuit shown in Figure 1 is a complete thermocouple system based on the AD7793 24-bit sigma-delta (Σ-Δ) analog-to-digital converter (ADC). The AD7793 is a low power, low noise, complete analog front end for high precision measurement applications. The device includes a programmable gain amplifier (PGA), an internal reference, an internal clock, and excitation currents, thereby greatly simplifying the thermocouple system design.
The AD7793 consumes only 500 μA maximum, making it suitable for any low power application, such as smart transmitters where the complete transmitter must consume less than 4 mA. The AD7793 has a power-down option. In this mode, the complete ADC, along with its auxiliary functions, is powered down so that the part consumes 1 μA maximum.
Because the AD7793 provides an integrated solution for thermocouple design, it interfaces directly to the thermocouple. For the cold junction compensation, a thermistor along with a precision resistor is used. These are the only external components required for the cold junction measurement other than some simple RC filters for EMC considerations.

Figure 1. Thermocouple Measurement System with Cold Junction Compensation (Simplified Schematic: All Connections and Decoupling Not Shown)
Применяемые компоненты
Applications
CN0255

This circuit uses the AD7988-1, a low power (350 μA) PulSAR® analog-to- digital converter (ADC), driven directly from the ADA4841-1 high performance, low voltage, low power op amp. This amplifier was chosen for its excellent dynamic performance and its ability to operate with a single-supply voltage and to provide a rail-to-rail output. In addition, the input commonmode voltage range includes the negative rail.
The AD7988-1 ADC requires an external voltage reference between 2.4 V and 5.1 V. In this application, the voltage reference chosen was the ADR4525 precision 2.5 V reference.

Применяемые компоненты
Applications
CN0251

The circuit shown in Figure 1 is a flexible signal conditioning circuit for processing signals of wide dynamic range, varying from several mV p-p to 20 V p-p. The circuit provides the necessary conditioning and level shifting and achieves the dynamic range using the internal programmable gain amplifier (PGA) of the high resolution analog-to-digital converter (ADC).
A ±10 V full-scale signal is very typical in process control and industrial automation applications; however, in some situations, the signal can be as small as several mV. Attenuation and level shifting is necessary to process a ±10 V signal with modern low voltage ADCs. However, amplification is needed for small signals to make use of the dynamic range of the ADC. Therefore, a circuit with a programmable gain function is desirable when the input signal varies over a wide range.
In addition, small signals may have large common-mode voltage swings; therefore, high common-mode rejection (CMR) is required. In some applications, where the source impedance is large, high impedance is also necessary for the analog front-end input circuit.

The circuit shown in Figure 1 solves all of these challenges and provides programmable gain, high CMR, and high input impedance. The input signal passes through the 4-channel ADG1409 multiplexer into the AD8226 low cost, wide input range instrumentation amplifier. The AD8226 offers high CMR up to 80 dB and very high input impedance (800 MΩ differential mode and 400 MΩ common mode). A wide input range and rail-to-rail output allow the AD8226 to make full use of the supply rails.
The AD8475 is a fully differential, attenuating amplifier with integrated precision gain resistors. It provides precision attenuation (G = 0.4 or G = 0.8), common-mode level shifting, and single-ended-to-differential conversion. The AD8475 is an easy to use, fully integrated precision gain block, designed to process signal levels up to ±10 V on a single supply. Therefore, the AD8475 is suitable for attenuating signals from the AD8226 up to 20 V p-p, while maintaining high CMR and offering a differential output to drive the differential input ADC.
The AD7192 is a 24-bit sigma-delta (Σ-Δ) ADC with an internal PGA. The on-chip, low noise gain stage (G = 1, 8, 16, 32, 64, or 128) means that signals of large and small amplitude can be interfaced directly to the ADC.
With the combination of the previous parts, the circuit offers very good performance and easy configuration for signals with varying amplitudes. The circuit can be used in industrial automation, process control, instrumentation, and medical equipment applications.
Применяемые компоненты
ADG1409
4 Ω Ron, 4-Channel ±15 V/+12 V/±5 V iCMOS Multiplexer
AD7192
24-разрядный сигма-дельта АЦП с крайне низким шумом и программируемым усилителем, частота выходных данных 4.8 кГц
AD8226
Инструментальный усилитель с широким диапазоном напряжений питания и Rail-to-Rail выходом
AD8475
Precision, Selectable Gain, Fully Differential Funnel Amplifier
ADP1720
Высоковольтный, микропотребляющий линейный стабилизатор, выходной ток 50 мА
ADR444
Ultralow Noise, LDO XFET® 4.096V Voltage Reference w/Current Sink and Source
Applications
CN0183

The circuit shown in Figure 1 provides a precision 16-bit, low drift bipolar voltage output of ±2.5 V and operates on a single +10 V to +15 V supply. The unipolar voltage outputs of the AD5668 octal denseDAC are amplified and level shifted by the AD8638 auto-zero op amps. The maximum drift contribution of the AD8638 is only 0.06 ppm/°C. The external REF192 reference ensures a maximum drift of 5 ppm/°C (E grade) and provides a low impedance pseudo ground for the AD8638 level gain and shifting circuit.
The circuit offers an efficient solution to a problem often encountered in systems with a single +12 V supply rail. Proper printed circuit board (PCB) layout and grounding techniques ensure that the ADP2300 switching regulator does not degrade the overall performance of the circuit.

Применяемые компоненты
AD8638
Операционный усилитель с автоматической коррекцией нуля и Rail-to-Rail выходом, питание 16 В
AD5668
Octal, 16-Bit, SPI Voltage Output denseDAC With 5 ppm/°C On-Chip Reference
ADP2300
Несинхронный понижающий импульсный стабилизатор 1.2 A/20 В, 700 кГц
REF192
2.5V Precision Micropower, Low Dropout, Low Voltage Reference
Applications
CN0179

The circuit in Figure 1 is a 4 mA-to-20 mA current loop transmitter for communication between a process control system and its actuator. Besides being cost effective, this circuit offers the industry’s low power solution. The 4 mA-to-20 mA current loop has been used extensively in programmable logic controllers (PLCs) and distributed control systems (DCS’s), with digital or analog inputs and outputs. Current loop interfaces are usually preferred because they offer the most cost effective approach to long distance noise immune data transmission. The combination of the low power AD8657 dual op amp, AD5641DAC, and ADR02 reference allows more power budget for higher power devices, such as microcontrollers and digital isolators. The circuit output is 0 mA to 20 mA of current, and it operates on a single supply from 8 V to 18 V. The 4 mA to 20 mA range is usually mapped to represent the input control range from the DAC or micro-controller, while the output current range of 0 mA to 4 mA is often used to diagnose fault conditions.
The 14-bit, 5 V AD5641 requires 75 μA typical supply current. The AD8657 is a rail-to-rail input/output dual op amp and is one of the lowest power amplifiers currently available in the industry (22 μA per amplifier over the full supply voltage and input common-mode range) with high operating voltage of up to 18 V. The ADR02 ultracompact precision 5 V voltage reference requires only 650 μA. Together, these three devices consume a typical supply current of 747 μA.
The circuit has a 12-pin Pmod™ digital interface (Digilent specification).

Применяемые компоненты
Applications
CN0175

Cost sensitive, high channel count applications that require wide dynamic range can effectively use the AD7607 8-channel integrated data acquisition system (DAS) with on-chip 14-bit SAR ADCs to achieve greater than 80 dB dynamic range.
A typical application for the DAS is in power-line measurementand protection equipment, where large numbers of current and voltage channels of multiphase distribution and transmission networks must be sampled simultaneously.
Many low voltage power-line measurement and protection systems do not require full 16-bit ADC resolution (such as provided by the AD7606 DAS); however, they still require more than 80 dB dynamic range to capture the under- and over- voltage/current conditions. Simultaneous sampling is also needed to maintain the phase information between the current and voltage channels on a multiphase power line.
The AD7607 8-Channel DAS with 14-Bit, bipolar input, simultaneous sampling SAR ADC has 84 dB signal-to-noise ratio (SNR) to meet the requirements for these types of low voltage protection and measurement systems. The circuit shown in Figure 1 also uses an external ADR421 precision, low drift, low noise reference for high channel count applications that require absolute accuracy performance.

Применяемые компоненты
Applications
CN0177

The circuit shown in Figure 1 provides a programmable 18-bit voltage with an output range −10 V to +10 V, ±0.5 LSB integral nonlinearity, ±0.5 LSB differential nonlinearity, and low noise.
The digital input to the circuit is serial and is compatible with standard SPI, QSPI, MICROWIRE®, and DSP interface standards. For high accuracy applications, the circuit offers high precision, as well as low noise—this is ensured by the combination of the AD5781, ADR445 and AD8676 precision components.
The reference buffer is critical to the design because the input impedance at the DAC reference input is heavily code dependent and will lead to linearity errors if the DAC reference is not adequately buffered. With a high open-loop gain of 120 dB, the AD8676 has been proven and tested to meet the settling time, offset voltage, and low impedance drive capability required by this circuit application. The AD5781 is characterized and factory calibrated using the AD8676 dual op amp to buffer its voltage reference inputs, further enhancing confidence in partnering the components.
This combination of parts provides industry-leading 18-bit integral nonlinearity (INL) of ±0.5 LSB and differential nonlinearity (DNL) of ±0.5 LSB, with guaranteed monotonicity, as well as low power, small PCB area, and cost effectiveness.

Применяемые компоненты
Applications
CN0260

This circuit, shown in Figure 1, is a flexible sensor signal conditioning block, with low noise, relatively high gain, and the ability to dynamically change the gain in response to input level changes without affecting performance, while still maintaining a wide dynamic range. Existing sigma-delta technology can provide the dynamic range needed for many applications, but only at the expense of low update rates. This circuit presents an alternative approach that uses the AD7985 16-bit, 2.5 MSPS PulSAR® successive-approximation ADC, combined with an autoranging AD8253 iCMOS® programmable gain instrumentation amplifier (PGA) front end. With gain that changes automatically based on analog input value, it uses oversampling and digital processing to increase the dynamic range of the system to more than 125 dB.


Применяемые компоненты
ADR439
Ultralow Noise XFET® 4.5V Voltage Reference w/Current Sink and Source Capability
AD8021
Быстродействующий усилитель с низким шумом для 16-разрядных систем
AD8253
Инструментальный усилитель iCMOS® с программируемым коэффициентом усиления G = 1, 10, 100, 1000, полоса 10 МГц
AD7985
16-Bit, 2.5 MSPS PulSAR 11 mW ADC in QFN
ADA4004-2
Прецизионный двухканальный усилитель, шум 1.8 нВ/√Гц, питание 36 В
Applications
CN0313

The circuits shown in Figure 1 demonstrate proven and tested electromagnetic compatibility (EMC) compliant solutions for three protection levels for popular RS-485 communication ports using the ADM3485E transceiver. Each solution was tested and characterized to ensure that the dynamic interaction between the transceiver and the protection circuit components functions correctly together to protect against the electrostatic discharge (ESD), electrical fast transients (EFT), and surge immunity specified in IEC 61000-4-2, IEC 61000-4-4, and IEC 61000-4-5, respectively. The circuits offer proven protection for RS-485 interfaces using the ADM3485E to the ESD, EFT, and surge levels often encountered in harsh environments.

Применяемые компоненты
ADM3485E
3.3 V, ±15 kV ESD-Protected, RS-485/RS-422 Transceiver (Half Duplex, 12Mbps, DE/RE)
Applications
Технологии оснащения зданий
- Отопление, вентиляция и кондиционирование воздуха
CN0267

The circuit shown in Figure 1 is a complete smart industrial, loop powered field instrument with 4 mA to 20 mA analog output and a highway addressable remote transducer (HART®) interface. HART is a digital 2-way communication in which a 1 mA peak-to-peak frequency-shift-keyed (FSK) signal is modulated on top of the standard 4 mA to 20 mA analog current signal. This allows features such as remote calibration, fault interrogation, and transmission of process variables, which are necessary in applications such as temperature and pressure control.
This circuit has been compliance tested, verified, and registered by the HART Communication Foundation (HCF). This successful registration provides circuit designers with a high level of confidence using one or all of the components in the circuit.
The circuit uses the ADuCM360, an ultralow power, precision analog microcontroller, the AD5421, a 16-bit, 4 mA to 20 mA, loop powered digital-to-analog converter (DAC), and the AD5700, the industry’s lowest power and smallest footprint HART compliant IC modem.


Применяемые компоненты
AD5421
16-разрядный ЦАП с выходом тока 4-20 мА, последовательным входом и питанием от токовой петли
AD5700
Малопотребляющий HART модем
AD5700-1
Малопотребляющий HART модем с прецизионным внутренним генератором
ADUCM360
Малопотребляющий прецизионный аналоговый микроконтроллер, ARM Cortex M3 с двумя сигма-дельта АЦП
ADuCM362
Low Power, Precision Analog Microcontroller with Dual Sigma-Delta ADCs, ARM Cortex-M3
ADuCM363
Low Power, Precision Analog Microcontroller with Single Sigma-Delta ADC, ARM Cortex-M3
Applications
CN0318

Maximum integral nonlinearity (INL) is ±0.5 LSB, and maximum differential nonlinearity (DNL) is ±0.5 LSB for the AD5760 voltage output DAC (B-grade).
The complete system has less than 0.1 LSB peak-to-peak noise and drift measured over a 100 second interval. The circuit is ideal for medical instrumentation, test and measurement, and industrial control applications where precision low drift voltage sources are required.

Figure 1. 16-Bit Accurate, ±10 V Voltage Source (Simplified Schematic: All Connections and Decoupling Not Shown)
Применяемые компоненты
Applications
CN0325


The evaluation board contains two different fully isolated universal input channels, one with a 4-pin terminal block (CH2), and one with a 6-pin terminal block (CH1).
For the 4-terminal block channel (CH2), the voltage, current, thermocouple, and RTD inputs all share the same 4 terminals, thus minimizing the number of terminal pins required. For the 6-pin terminal block channel (CH1), the voltage and current inputs share a set of 3 terminals, and the thermocouple and RTD inputs share another set of 3 terminals; this configuration requires more terminals but has a lower part count and component cost. Figure 2 shows a photo of the printed circuit board (PCB), and Figure 3 shows a more detailed schematic of the circuit.


Применяемые компоненты
AD7795
Шестиканальный, малопотребляющий 16-разрядный сигма-дельта АЦП с низким шумом, интегрированным ИУ и источником опорного напряжения
ADR441
Ultralow Noise, LDO XFET® 2.5V Voltage Reference w/Current Sink and Source
ADUM1311
Triple-Channel Digital Isolators
ADG442
LC2MOS Quad SPST Switch
AD8226
Инструментальный усилитель с широким диапазоном напряжений питания и Rail-to-Rail выходом
ADT7310
16-разрядный цифровой датчик температуры с интерфейсом SPI, погрешность ±0.5°C
ADP2441
Синхронный понижающий стабилизатор постоянного напряжения, 36 В/1 А
ADUM3471
Isolated Switching Regulators (3/1 Channel Directionality)
ADP1720
Высоковольтный, микропотребляющий линейный стабилизатор, выходной ток 50 мА
Applications
CN0247

The circuit shown in Figure 1 is an ultralow, power data acquisition system using the AD7091R 12-bit, 1 MSPS SAR ADC and an AD8031 op amp driver with a total circuit power dissipation of less than 5 mW on a single 3 V supply.
The low power consumption and small package size of the selected components makes this combination an industryleading solution for portable battery-operated systems where power dissipation, cost, and size play a critical role.
The AD7091R requires typically only 350 μA of supply current on the VDD pin at 3 V, which is significantly lower than any competitive ADC offering currently available in the market. This translates to ~1 mW typical power dissipation.
The AD8031 requires only 800 μA of supply current, that results in 2.4 mW typical power dissipation at 3 V supply, making the total power dissipation of the system less than 5 mW when sampling at 1 MSPS with a 10 kHz analog input signal.

Figure 1. 12-Bit, 1 MSPS Low Power ADC with Driver (Simplified Schematic: All Connections Not Shown)
Применяемые компоненты
Applications
CN0191

The circuit shown in Figure 1 provides a programmable 20-bit voltage with an output range −10 V to +10 V, ±1 LSB integral nonlinearity, ±1 LSB differential nonlinearity, and low noise.
The digital input to the circuit is serial and is compatible with standard SPI, QSPI™, MICROWIRE®, and DSP interface standards. For high accuracy applications, the circuit offers high precision, as well as low noise, and this is ensured by the combination of the AD5791, AD8675, and AD8676 precision components.
The reference buffer is critical to the design because the input impedance at the DAC reference input is heavily code dependent and will lead to linearity errors if the DAC reference is not adequately buffered. With a high open-loop gain of 120 dB, the AD8676 has been proven and tested to meet the settling time, offset voltage, and low impedance drive capability required by this circuit application. The AD5791 is characte-rized and factory calibrated using the AD8676 dual op amp to buffer its voltage reference inputs, further enhancing confidence in partnering the components.
This combination of parts provides industry-leading 20-bit integral nonlinearity (INL) of ±1 LSB and differential nonlinearity (DNL) of ±1 LSB, with guaranteed monotonicity, as well as low power, small PCB area, and cost effectiveness.
Figure 1. 20-Bit Accurate, ±10 V Voltage Source (Simplified Schematic: All Connections and Decoupling Not Shown)
Применяемые компоненты
Applications
CN0180

Whereas suitable interface circuits can be designed using resistor networks and dual op amps, errors in the ratio matching of the resistors, and between the amplifiers, produce errors at the final output. Achieving the required output phase matching and settling time can be a challenge, especially at low power levels.
The circuit shown in Figure 1 uses the AD8475 differential funnel amplifier to perform attenuation, level shifting, and conversion to differential without the need for any external components. The ac and dc performances are compatible with those of the 18-bit, 1 MSPS AD7982 PulSAR® ADC and other 16- and 18-bit members of the family, which have sampling rates up to 4 MSPS.
The AD8475 is a fully differential attenuating amplifier with integrated precision thin film gain setting resistors. It provides precision attenuation (by 0.4× or 0.8×), common-mode level shifting, and single-ended-to-differential conversion along with input overvoltage protection. Power dissipation on a single 5 V supply is only 15 mW. The 18-bit, 1 MSPS AD7982 consumes only 7 mW, which is 30× lower than competitive ADCs. The total power dissipated by the combination is only 22 mW.
Применяемые компоненты
Applications
CN0202

The circuit also contains key features for industrial applications, such as on-chip output fault detection and protection (short circuit, undervoltage output, open circuit current output, and overtemperature), CRC checking to prevent packet error (PEC), and flexible power-up options, making it an ideal choice for robust industrial control systems. No external precision resistors or calibration routines are needed to maintain consistent performance in mass production, thereby making it ideal for PLC or DCS modules.
Figure 1. Basic Analog Output Circuit for Single Channel (Simplified Schematic, All Connections and Protection Circuits Not Shown)
Применяемые компоненты
Applications
CN0204

The AD5662 low power (0.75 mW typical @ 5 V), rail-to-rail output, 16-bit nanoDAC® device and the AD5751 industrial current/voltage output driver are well matched with respect to input and output voltage ranges, as well as reference voltage requirements.
The ADR444, with low drift (3 ppm/℃ maximum for B grade), high initial accuracy (0.04% maximum for B grade), and low noise (1.8 μV p-p typical, 0.1 Hz to 10 Hz), provides the reference voltage for both the AD5751 and AD5662 and guarantees ultralow noise, high accuracy, and low temperature drift for the circuit. This circuit provides all the typical voltage and current output ranges with 16-bit resolution and no missing codes, 0.05% linearity, and less than 0.2% total output error.
The ADuM1301 and ADuM5401 provide all the necessary signal isolation between the microcontroller and the analog signal chain. The ADuM5401 also provides isolated 5 V power. The circuit also contains key features for industrial applications, such as on-chip output fault detection, CRC checking to prevent packet error (PEC), and flexible power-up options, making it an ideal choice for robust industrial control systems. No external precision resistors or calibration routines are needed to maintain consistent performance in mass production, thereby making it ideal for PLC or DCS modules.
Figure 1. Basic Analog Output Circuit for Single Channel (Simplified Schematic, All Connections and Protection Circuits Not Shown)
Применяемые компоненты
AD5662
2.7-5.5V, 16-Bit nanoDAC® Converter in a Sot-23
ADUM1301
Triple-Channel Digital Isolator
ADUM5401
Quad-Channel, 2.5 kV Isolators with Integrated DC-to-DC Converter (3/1 channel directionality)
AD5751
Промышленный драйвер токовой петли с выходом по току и напряжению с программируемыми выходными диапазонами
ADR444
Ultralow Noise, LDO XFET® 4.096V Voltage Reference w/Current Sink and Source
Applications
CN0209

The circuit shown in Figure 1 provides a fully programmable universal analog front end (AFE) for process control applications. The following inputs are supported: 2-, 3-, and 4- wire RTD configurations, thermocouple inputs with cold junction compensation, unipolar and bipolar input voltages, and 4 mA-to-20 mA inputs.
Today, many analog input modules use wire links (jumpers) to configure the customer input requirements. This requires time, knowledge, and manual intervention to configure and reconfigure the input. This circuit provides a software controllable switch to configure the modes along with a constant current source to excite the RTD. The circuit is also reconfigurable to set common-mode voltages for the thermocouple configuration. A differential amplifier is used to condition the analog input voltage range to the Σ-Δ ADC. The circuit provides industry-leading performance and cost.
Because of the voltage gain provided by the AD8676 and AD8275, the design is particularly suitable for small signal inputs, all types of RTDs, or thermocouples.
The AD7193 is a 24-bit Σ-Δ ADC that can be configured to have four differential inputs or eight pseudo differential inputs. The ADuM1400 and ADuM1401 provide all the necessary signal isolation between the microcontroller and the ADC. The circuit also includes standard external protection and is compliant with the IEC 61000 specifications.
Figure 1. Universal Programmable Analog Front End for Process Control Applications (Simplified Schematic: All Connections and Decoupling Not Shown)
Применяемые компоненты
AD8676
Ultra Precision, 36 V, 2.8 nV/√Hz Dual RRO Op Amp
ADG442
LC2MOS Quad SPST Switch
AD8275
Драйвер 16-разрядных АЦП с преобразованием уровня сигнала, G = 0.2
ADT7310
16-разрядный цифровой датчик температуры с интерфейсом SPI, погрешность ±0.5°C
AD7193
Четырехканальный 24-разрядный сигма-дельта АЦП с крайне низким шумом и программируемый усилитель, частота выходных данных 4.8 кГц
ADG1414
9.5 Ω RON ±15 V/+12 V/±5 V iCMOS Serially-Controlled Octal SPST Switches
ADUM1401
Quad-Channel Digital Isolator (3/1 Channel Directionality)
ADUM1400
Quad-Channel Digital Isolator (4/0 Channel Directionality)
ADP1720
Высоковольтный, микропотребляющий линейный стабилизатор, выходной ток 50 мА
REF194
4.5V Precision Micropower, Low Dropout, Low Voltage Reference
AD8617
Low Cost Micropower, Low Noise CMOS RRIO Dual Op Amp
Applications
CN0213

The analog front-end circuit shown in Figure 1 is optimized for high precision and high common-mode rejection ratio (CMRR) when processing these types of industrial-level signals.
Figure 1. High Performance Analog Front End for Process Control (Simplified Schematic: All Connections and Decoupling Not Shown)
The circuit level shifts and attenuates the signals so they are compatible with the input range requirements of most modern single-supply SAR ADCs, such as the AD7685 high performance 16-bit 250 kSPS PulSAR® ADC.
With an 18 V p-p input signal, the circuit achieves approximately 105 dB common-mode rejection (CMR) at 100 Hz and 80 dB CMR at 5 kHz.
High precision, high input impedance, and high CMR are provided by the AD8226 instrumentation amplifier. For high precision applications, a high input impedance is required to minimize system gain errors and also to achieve good CMR. The AD8226 gain is resistor-programmable from 1 to 1000.
A resistive level shifter/attenuator stage directly on the input would inevitably degrade CMR performance due to the mismatch between the resistors. The AD8226 provides the excellent CMR required for both small signal and large signal inputs. The AD8275 level shifter/attenuator/driver performs the attenuation and level shifting function in the circuit, without any need for external components.
Traditionally, sigma-delta ADCs have been used in high resolution measurement systems because signal bandwidths are quite low, and the sigma-delta architecture provides excellent noise performance at low update rates. However, there is an increased trend for higher update rates, especially in multichannel systems, to allow faster per-channel update, or for increased channel density. In such cases a high performance SAR ADC is a good alternative. The circuit shown in Figure 1 uses the AD7685 250 kSPS 16 bit ADC, with the AD8226 high performance in-amp, and the AD8275 attenuator/level shifter amplifier implemented as a complete system solution without the need for any external components.
Применяемые компоненты
AD7685
16-разрядный АЦП PulSAR® в корпусах MSOP/QFN, быстродействие 250 kSPS
AD8226
Инструментальный усилитель с широким диапазоном напряжений питания и Rail-to-Rail выходом
AD8275
Драйвер 16-разрядных АЦП с преобразованием уровня сигнала, G = 0.2
ADP1720
Высоковольтный, микропотребляющий линейный стабилизатор, выходной ток 50 мА
ADR439
Ultralow Noise XFET® 4.5V Voltage Reference w/Current Sink and Source Capability
Applications
CN0257

The AD8675 precision op amp has low offset voltage (75 μV maximum) and low noise (2.8 nV/√Hz typical) and is an optimum output buffer for the AD5790. The AD5790 has two internal matched 6.8 kΩ feedforward and feedback resistors, which can either be connected to the AD8675 op amp to provide a 10 V offset voltage for a ±10 V output swing, or connected in parallel to provide bias current cancellation. In this example, a unipolar +10 V output is demonstrated, and the resistors are used for bias current cancellation. The internal resistor connection is controlled by setting a bit in the AD5790 control register (see AD5790 data sheet).
The digital input to the circuit is serial and is compatible with standard SPI, QSPI, MICROWIRE®, and DSP interface standards. For high accuracy applications, the compact circuit offers high precision, as well as low noise—this is ensured by the combination of the AD5790 and AD8675 precision components.
Figure 1. 20-Bit Accurate, 0 V to +10 V Voltage Source (Simplified Schematic: All Connections and Decoupling Not Shown)
Применяемые компоненты
Applications
CN0200

The AD8675 precision op amp has low offset voltage (75 μV maximum), low noise (2.8 nV/√Hz typical), and is an optimum output buffer for the AD5780. The AD5780 has two internal matched feedforward and feedback resistors, which are connected to the AD8675 op amp and provide the 10 V offset voltage. This allows an output voltage swing of ±10 V with a single external 10 V reference.
The digital input to the circuit is serial and is compatible with standard SPI, QSPI, MICROWIRE®, and DSP interface standards. For high accuracy applications, the compact circuit offers high precision, as well as low noise—this is ensured by the combination of the AD5780, ADR445, and AD8675 precision components.
This combination of parts provides industry-leading 18-bit integral nonlinearity (INL) of ±1 LSB and differential nonlinearity (DNL) of ±0.75 LSB, with guaranteed monotonicity, as well as low power, small PCB area, and cost effectiveness in an LFCSP package.
Figure 1. 18-Bit Accurate, ±10V Voltage Source (Simplified Schematic: All Connections and Decoupling Not Shown)
Применяемые компоненты
Applications
CN0194

Figure 1. Galvanically Isolated, 2-Channel, Simultaneous Sampling, 16-Bit Analog-to-Digital Conversion System with Daisy Chain (Simplified Schematic: All Connections and Decoupling Not Shown)
Применяемые компоненты
Applications
CN0254

Применяемые компоненты
AD8605
Precision, Low Noise, CMOS, RRIO Op Amp (single)
AD8609
Precision Quad MicroPower Rail-to-Rail Input/Output Amplifier
AD7689
16-битный 8-канальный АЦП PulSAR® с быстродействием 250 kSPS
ADUM3471
Isolated Switching Regulators (3/1 Channel Directionality)
ADP3336
Миниатюрный LDO-стабилизатор anyCAP® с регулируемым выходным напряжением, выходной ток 500 мА
AD8608
Low Noise, CMOS, Rail-to-Rail, Input/Output Precision Quad Op Amp
Applications
CN0345

The circuit shown in Figure 1 is a cost effective, low power, multichannel data acquisition system that is compatible with standard industrial signal levels. The components are specifically selected to optimize settling time between samples, providing 18-bit performance at channel switching rates up to approximately 750 kHz.

The circuit can process eight gain-independent channels and is compatible with both single-ended and differential input signals.
The analog front end includes a multiplexer, programmable gain instrumentation amplifier (PGIA); precision analog-to-digital converter (ADC) driver for performing the single-ended to differential conversion; and an 18-bit, 1 MSPS PulSAR® ADC for sampling the signal on the active channel. Gain configurations of 0.4, 0.8, 1.6, and 3.2 are available.
The maximum sample rate of the system is 1 MSPS. The channel switching logic is synchronous to the ADC conversions, and the maximum channel switching rate is 1 MHz. A single channel can be sampled at up to 1 MSPS with 18-bit resolution. Channel switching rates up to 750 kHz also provide 18-bit performance. The system also features low power consumption, consuming only 240 mW at the maximum ADC throughput rate of 1 MSPS.
Применяемые компоненты
AD7982
18-Bit, 1 MSPS PulSAR 7 mW ADC in MSOP/LFCSP
AD8251
10 MHz, G = 1, 2, 4, 8 iCMOS® Programmable Gain Instrumentation Amplifier
ADR434
Low Noise XFET® Voltage References with Current Sink and Source Capability
ADG1207
Low Capacitance, 8-Channel, ±15 V/+12 V iCMOS Multiplexer
AD8475
Precision, Selectable Gain, Fully Differential Funnel Amplifier
Applications
CN0310

This circuit solves the problem of acquiring and digitizing the standard industrial signal levels of ±5 V, ±10 V, and 0 V to 10 V
with precision ADCs having low supply voltages by using an
innovative differential amplifier with internal laser trimmed
resistors to perform the attenuation and level shifting. Applications
for the circuit include process controls (PLC/DCS modules), medical, and scientific multichannel instrumentation and chromatography.

Применяемые компоненты
Applications
CN0269

A single channel can be sampled at up to 1.33 MSPS with 18-bit resolution. A channel-to-channel switching rate of 250 kHz between all input channels provides 16-bit performance.
The signal processing circuit combined with a simple 4-bit up-down binary counter provides a simple and cost effective way to realize channel-to-channel switching without an FPGA, CPLD, or high speed processor. The counter can be programmed to count up or count down for sequentially sampling multiple channels, or can be loaded with a fixed binary word for sampling a single channel.
This circuit is an ideal solution for a multichannel data acquisition card for many industrial applications including process control, and power line monitoring.

Figure 1. Multichannel Data Acquisition Circuit (Simplified Schematic: All Components, Connections, and Decoupling Not Shown)
Применяемые компоненты
AD8065
Высокопроизводительный ОУ FastFET™ с шириной полосы 145 МГц
AD8475
Precision, Selectable Gain, Fully Differential Funnel Amplifier
ADG5236
High Voltage Latch-Up Proof, Dual SPDT Switches
ADG5208
High Voltage Latch-Up Proof, 4-/8-Channel Multiplexers
AD7984
18-битный, 1.33 MSPS 10,5 мВт АЦП импульсного радиоизлучения в MSOP/QFN корпусе
ADR444
Ultralow Noise, LDO XFET® 4.096V Voltage Reference w/Current Sink and Source
Applications
CN0201


A single +5 V supply powers the circuit, and a high efficiency, low ripple boost converter generates the ±15 V that allows processing differential input signals up to ±24.576 V with ±2 LSB INL (maximum), and ±0.5 LSB DNL (typical). For high accuracy applications, this compact and cost-effective circuit offers high precision, as well as low noise.
The successive approximation register (SAR)-based data acquisition system includes true high impedance differential input buffers; therefore, there is no need for additional buffering, as is usually required to reduce kickback in capacitive digital-toanalog converter (DAC)-based SAR analog-to-digital converters (ADCs). In addition, the circuit has high common-mode rejection, eliminating the need for external instrumentation amplifiers, which are typically required in applications where common-mode signals are present.
The ADAS3022 is a complete 16-bit, 1 MSPS data acquisition system that integrates an 8-channel, low leakage multiplexer; a programmable gain instrumentation amplifier stage with a high common-mode rejection; a precision low drift 4.096 V reference; a reference buffer; and a high performance, no latency, 16-bit SAR ADC. The ADAS3022 reduces its power at the end of each conversion cycle; therefore, the operating currents and power scale linearly with throughput make it ideal for the low sampling rates in battery-powered applications.
The ADAS3022 has eight inputs and a COM input that can be configured as eight single-ended channels, eight channels with a common reference, four differential channels, or various combinations of single-ended and differential channels.
In the circuit shown in Figure 1, the reference is supplied by the ADR434 low noise reference buffered by an AD8031 op amp. The AD8031 is ideally suited as a reference buffer because of its ability to drive dynamic loads with fast recovery.
The ADP1613 is a dc-to-dc boost converter with an integrated power switch and provides the ADAS3022 high voltage ±15 V supplies required for the on-chip input multiplexer and the programmable gain instrumentation amplifier without compromising the performance of the ADAS3022.
This circuit offers high precision, as well as low noise, which is ensured by the combination of the ADAS3022, ADP1613, ADR434, and AD8031 precision components.
Применяемые компоненты
AD8032
2.7 V, 800 µA, 80 MHz Rail-to-Rail I/O Dual Amplifier
AD8031
2.7 V, 800 µA, 80 MHz Rail-to-Rail I/O Single Amplifier
ADP1613
Повышающий импульсный преобразователь постоянного напряжения с ШИМ и предельным током 2.0 А, 650 кГц/1.3 МГц
ADAS3022
16-разрядная, 8-канальная система сбора данных с быстродействием 1 MSPS
ADR434
Low Noise XFET® Voltage References with Current Sink and Source Capability
ADAS3023
16-Bit, 8-Channel Simultaneous Sampling Data Acquisition System
Applications
CN0384


Figure 1. AD7124-4/AD7124-8 Thermocouple Measurement Configuration Including RTD Cold Junction Compensation
The AD7124-4 can be configured for 4 differential or 7 pseudo differential input channels, while the AD7124-8 can be configured for 8 differential or 15 pseudo differential channels. The on-chip low noise programmable gain array (PGA) ensures that signals of small amplitude can be interfaced directly to the ADC.
The AD7124-4/AD7124-8 establishes the highest degree of signal chain integration, which includes programmable low drift excitation current sources, bias voltage generator, and internal reference. Therefore, the design of a thermocouple system is simplified when the AD7124-4/AD7124-8 is used because most of the required system building blocks are included on-chip.
The AD7124-4/AD7124-8 gives the user the flexibility to employ one of three integrated power modes, where the current consumption, range of output data rates, and rms noise are tailored with the power mode selected. The current consumed by the AD7124-4/AD7124-8 is only 255 μA in low power mode and 930 μA in full power mode. The power options make the device suitable for non-power critical applications, such as input/output modules, and also for low power applications, such as loop-powered smart transmitters where the complete transmitter must consume less than 4 mA.
The device also has a power-down option. In power-down mode, the complete ADC along with its auxiliary functions are powered down so that the device consumes 1 μA typical. The AD7124-4/AD7124-8 also has extensive diagnostic functionality integrated as part of its comprehensive feature set.
Применяемые компоненты
AD7124-4
Четырехканальный 24-разрядный сигма-дельта АЦП с низким шумом, малым энергопотреблением, интегрированными усилителем и источником опорного напряжения
AD7124-8
Восьмиканальный, малопотребляющий 24-разрядный сигма-дельта АЦП с низким шумом, программируемым усилителем и источником опорного напряжения
ADP1720
Высоковольтный, микропотребляющий линейный стабилизатор, выходной ток 50 мА
Applications
CN0381

The circuit shown in Figure 1 is an integrated 4-wire, resistance temperature detector (RTD) system based on the AD7124-4/AD7124-8 low power, low noise, 24-bit Σ-Δ ADC optimized for high precision measurement applications. With a two-point calibration and linearization, the overall 4-wire system accuracy is better than ±1°C over a temperature range of −50°C to +200°C. Typical noise free code resolution of the system is 17.9 bits for full power mode, sinc4 filter selected, at an output data rate of 50 SPS, and 17.3 bits for low power mode, post filter selected, and at an output data rate of 25 SPS.
The AD7124-4 can be configured for 4 differential or 7 pseudo differential input channels, while the AD7124-8 can be configured for 8 differential or 15 pseudo differential input channels. The on-chip programmable gain array (PGA) ensures that signals of small amplitude can be interfaced directly to the ADC.
The AD7124-4/AD7124-8 establishes the highest degree of signal chain integration, which include programmable low drift excitation current sources. Therefore, the design of an RTD system is greatly simplified because most of the required RTD measurement system building blocks are included on-chip.
The AD7124-4/AD7124-8 gives the user the flexibility to employ one of three integrated power modes, where the current consumption, range of output data rates, and rms noise are tailored with the power mode selected. The current consumed by the AD7124-4/AD7124-8 is only 255 μA in low power mode and 930 μA in full power mode. The power options make the device suitable for non-power critical applications, such as input/output modules, and also for low power applications such as loop powered smart transmitters where the complete transmitter must consume less than 4 mA.
The device also has a power-down option. In power-down mode, the complete ADC along with its auxiliary functions are powered down so that the device consumes 1 μA typical. The AD7124-4/AD7124-8 also has extensive diagnostic functionality integrated as part of its comprehensive feature set.

Применяемые компоненты
AD7124-4
Четырехканальный 24-разрядный сигма-дельта АЦП с низким шумом, малым энергопотреблением, интегрированными усилителем и источником опорного напряжения
AD7124-8
Восьмиканальный, малопотребляющий 24-разрядный сигма-дельта АЦП с низким шумом, программируемым усилителем и источником опорного напряжения
ADP1720
Высоковольтный, микропотребляющий линейный стабилизатор, выходной ток 50 мА
Applications
CN0383

The circuit shown in Figure 1 is an integrated 3-wire resistance temperature detector (RTD) system based on the AD7124-4/AD7124-8 low power, low noise, 24-bit Σ-Δ analog-to-digital converter (ADC) optimized for high precision measurement applications. With a two-point calibration and linearization, the overall 3-wire system accuracy is better than ±1°C over a temperature range of −50°C to +200°C. Typical noise free code resolution of the system is 17.9 bits for full power mode, sinc4 filter selected, at an output data rate of 50 SPS, and 16.8 bits for low power mode, post filter selected, at an output data rate of 25 SPS.

The AD7124-4 can be configured for 4 differential or 7 pseudo differential input channels, while the AD7124-8 can be configured for 8 differential or 15 pseudo differential channels. The on-chip programmable gain array (PGA) ensures that signals of small amplitude can be interfaced directly to the ADC.
The AD7124-4/AD7124-8 establishes the highest degree of signal chain integration, which includes programmable low drift excitation current sources. Therefore, the design of an RTD system is greatly simplified because most of the required RTD measurement system building blocks are included on-chip.
The AD7124-4/AD7124-8 gives the user the flexibility to employ one of three integrated power modes, where the current consumption, range of output data rates, and rms noise are tailored with the power mode selected. The current consumed by the AD7124-4/AD7124-8 is only 255 μA in low power mode and 930 μA in full power mode. The power options make the device suitable for non-power critical applications, such as input/output modules, and also for low power applications, such as loop-powered smart transmitters where the complete transmitter must consume less than 4 mA.
The device also has a power down option. In power-down mode, the complete ADC along with its auxiliary functions are powered down so that the device consumes 1 μA typical. The AD7124-4/ AD7124-8 also has extensive diagnostic functionality integrated as part of its comprehensive feature set.
Применяемые компоненты
AD7124-4
Четырехканальный 24-разрядный сигма-дельта АЦП с низким шумом, малым энергопотреблением, интегрированными усилителем и источником опорного напряжения
AD7124-8
Восьмиканальный, малопотребляющий 24-разрядный сигма-дельта АЦП с низким шумом, программируемым усилителем и источником опорного напряжения
ADP1720
Высоковольтный, микропотребляющий линейный стабилизатор, выходной ток 50 мА
Applications
CN0376

The circuit shown in Figure 1 provides a dual-channel, channel-to-channel isolated, thermocouple or RTD input suitable for programmable logic controllers (PLC) and distributed control systems (DCS). The highly integrated design utilizes a low power, 24-bit, Σ-Δ analog-to-digital converter (ADC) with a rich analog and digital feature set that requires no additional signal conditioning ICs.
Each channel can accept either a thermocouple or a RTD input. The entire circuit is powered from a standard 24 V bus supply. Each channel measures only 27 mm × 50 mm.

Применяемые компоненты
AD7124-4
Четырехканальный 24-разрядный сигма-дельта АЦП с низким шумом, малым энергопотреблением, интегрированными усилителем и источником опорного напряжения
AD7124-8
Восьмиканальный, малопотребляющий 24-разрядный сигма-дельта АЦП с низким шумом, программируемым усилителем и источником опорного напряжения
ADUM5010
2.5kV rms Isolated DC/DC Converter
ADUM1441
Микропотребляющий четырехканальный цифровой изолятор, высокий логический уровень по умолчанию (конфигурация каналов 3/1)
ADP2441
Синхронный понижающий стабилизатор постоянного напряжения, 36 В/1 А
Applications
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Промышленный Ethernet
Поддержка многих существующих коммуникационных протоколов и стандартов проводной связи в современных системах управления на основе ПЛК или РСУ, а также учет потребностей коммуникационного оборудования будущего, приводят к тому, что разработка в области промышленного Ethernet становится важной задачей. ADI провела значительные исследования с целью нахождения решения этой задачи, и мы уже сотрудничаем с ведущими отраслевыми партнерами, что позволит обеспечить технологические процессы и производственные площадки возможностями Ethernet.
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Интерфейс и гальваническая изоляция
Узнайте больше о цифровых интерфейсах и решениях для обеспечения цифровых каналов гальванической изоляцией, которые соответствуют стандартам организации полевых шин и периферийных средств связи в составе систем управления на основе ПЛК и РСУ. Узнайте, как инновационные технологии позволили создать решения в области гальванической изоляции, которые не имеют ограничений, присущих оптопарам.
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Беспроводная связь
Изучите проверенное и надежное решение для беспроводной передачи данных, отвечающее требованиям промышленных приложений. SmartMesh и SmartMesh WirelessHART являются единственными беспроводными сетями, предназначенными для применения в самых суровых условиях промышленных предприятий, где основными факторами являются низкое энергопотребление, надежность, отказоустойчивость и масштабируемость.

Форм-фактор, КПД и электромагнитное излучение. В условиях предприятий Индустрии 4.0, заполненных потоками данных и оснащенных множеством датчиков, эти характеристики как никогда являются критически важными. Узнайте, как уникальные технологии ADI могут обеспечить превосходные результаты в каждой области без ухудшения характеристик.
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- Optimized Circuit Design for HART Enabled 4 mA to 20 mA Inputs
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- ADC Requirements for RTC Temperature Measurement Systems
Analog Dialogue
- Analog Front-End Design Considerations for RTD Ratiometric Temperature Measurements
- Minimizing Errors in Multiplexed 3-Wire RTD Data-Acquisition Systems
- Two Ways to Measure Temperature Using Thermocouples Feature Simplicity, Accuracy, and Flexibility
- Using ESD Diodes as Voltage Clamps
- Safeguard Your RS-485 Communication Networks from Harmful EMC Events
- PLC Evaluation Board Simplifies Design of Industrial Process-Control systems
- Understanding and Extending Safety Operation in a Sigma-Delta ADC
- Designing Robust Isolated RS-232 Data Interfaces for Harsh Industrial Applications
- Op Amp Input Overvoltage Protection: Clamping vs. Integrated
- Integrated Capacitive PGAs in ADCs: Redefining Performance
- Next-Generation SAR ADC Addresses Pain Points of Precision Data Acquisition Signal Chain Design
- Improving Precision Data Acquisition Signal Chain Density Using SiP Technology
- Ask The Applications Engineer—27: Signal Corruption in Industrial Measurement
- Quad 16-Bit Voltage-/Current-Output DACs Save Space, Cost, and Power in Multichannel PLCs
- PLC DCS Analog Input Module Design Breaks Barriers in Channel-to-Channel Isolation and High Density