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The AD7780 low-noise, low-power, 24-bit sigma-delta analog-to-digital converter with integrated PGA is used in low- to mid-end weigh scale systems. The radiated immunity of the system is tested as part of the release process. This 12-page Application Note describes how to achieve the best radiated immunity performance from the AD7780, taking into account the effects of layout and component placement when designing a printed circuit board (PCB). The radiated immunity testing is performed on the complete system (ADC, PCB, and load cell) as per standard IEC 61000-4-3.
The AD7292 monitor and control IC contains all the functionality required for general-purpose monitoring of analog signals and control of external devices, including an 8‑channel multiplexer, 10-bit SAR ADC, four 10-bit DACs, a ±1°C accurate internal temperature sensor, and 12 GPIOs to aid system monitoring and control. The DAC has an output voltage range up to 5 V (LSB of 4.88 mV). The output buffer can be controlled via software or hardware. This 4-page Application Note describes the timing associated with the DAC disable function.
This 15-page Application Note describes the calibration procedure for the ADE7880 high-accuracy, 3-phase electrical energy measurement IC, including equations and examples of how to calculate each constant. The ADE7880 incorporates second-order sigma-delta (Σ-Δ) analog-to-digital converters, a digital integrator, reference circuitry, and all of the signal processing required to measure the total (fundamental and harmonic) active and apparent energy and the fundamental-only active and reactive energy. In addition, it computes the rms of harmonics on the phase and neutral currents and on the phase voltages; the active, reactive, and apparent power; the power factor; and the harmonic distortion on each harmonic for all phases; and the total harmonic distortion plus noise (THD + N) for all currents and voltages.
Kalman Filter Estimates Orientation Angles Based on Sensor Data
The ADIS16480 MEMS inertial measurement unit (IMU) includes a 3-axis accelerometer, a 3-axis gyroscope, a 3-axis magnetometer, and a barometer. It also includes an extended Kalman filter (EKF) that computes dynamic orientation angles. The EKF estimates the orientation angles using a combination of gyroscope, accelerometer, and magnetometer contributions, with real-time filter weighting factors determined by covariance terms representing the level of uncertainty assigned to each sensor. Optimal performance comes from selecting appropriate covariance values for the sensors, given the application environment. This 8-page Application Note offers analytical tools for simplifying this process.
Simple Calibration Procedure Improves Performance of Energy Meter
This 9-page Application Note describes how to calibrate the ADE7816 energy metering IC, including equations and examples of how to calculate each constant. The ADE7816 is a high-accuracy multichannel metering IC that can measure the energy on up to six current channels. It provides a variety of energy measurements including active and reactive energy, along with rms current and voltage readings—and a variety of power quality features, including no load, reverse power, and angle measurement. The data can be accessed via SPI, I2C, or high-speed data-capture (HSDC) interfaces.
These circuits 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.
This dual-channel colorimeter, which features a modulated light source transmitter and a synchronous detector receiver, measures the ratio of light absorbed by the sample and reference containers at three different wavelengths, providing an efficient solution for many chemical analysis and environmental monitoring instruments that measure concentrations and characterize materials through absorption spectroscopy.
It is important to provide fast, high-resolution conversions when sampling industrial signals. Previously, the highest resolution analog-to-digital converters (ADCs) available at sampling rates up to 500 kSPS were 14 bit to 18 bit. This single-supply system is optimized for sampling industrial-level signals with a 24-bit, 250 kSPS sigma- delta (Σ-Δ) ADC. Each of the two differential or four pseudo-differential channels can be scanned at a rate up to 50 kSPS with 17.2 bits of noise-free code resolution. This circuit solves the problem of acquiring and digitizing standard industrial signal levels of ±5 V, ±10 V, and 0 V to 10 V with precision low-voltage ADCs by using an innovative differential amplifier with internal laser trimmed resistors to perform the attenuation and level shifting.
This combined 16-bit, 6-MSPS, successive-approximation (SAR) analog-to-digital converter (ADC) and differential-to-differential driver is optimized for low noise (88.6‑dB SNR), low distortion (−110 dBc THD), and low power dissipation. The SAR architecture can sample without latency, making it ideal for high-performance multiplexed data acquisition systems, such as portable digital x-ray systems and security scanners. The 6-MSPS sampling rate allows fast sampling of multiple channels, and the ADC has true 16-bit dc linearity and a LVDS interface for low pin count and low digital noise. The fast settling time (45 ns to 0.1%) of ADA4897-1 makes it ideal for multiplexed applications.
This circuit uses the ADuCM360 precision analog microcontroller in an accurate thermocouple temperature monitoring application to controls the 4-mA to 20-mA output current. The ADuCM360 integrates two 24-bit sigma-delta (Σ-Δ) analog-to-digital converters, two programmable current sources, a 12-bit digital-to-analog converter, a 1.2-V reference, an ARM Cortex-M3 core, 126 KB flash, 8 kB SRAM, and various digital peripherals, such as UART, timers, SPIs, and I2C interfaces. In the circuit, the ADuCM360 connects to a Type T thermocouple and a 100-Ω platinum resistance temperature detector, which is used for cold junction compensation. The low-power Cortex-M3 core converts the ADC readings to a real temperature value. The −200°C to +350°C Type T temperature range is converted to an output current range of 4 mA to 20 mA. The loop powered circuit operates with loop voltages up to 28 V to provide a complete solution for thermocouple measurements.
This complete, adjustment-free, linear variable differential transformer (LVDT) signal conditioning circuit can accurately measure linear displacement (position). It uses the AD598 LVDT signal conditioner, which integrates a sine wave oscillator and a power amplifier to generate the excitation signals that drive the primary side of the LVDT. The system has 82-dB dynamic range and 250-Hz bandwidth, making it ideal for precision industrial position and gauging applications. This Circuit Note discusses basic LVDT theory and the design steps used to optimize the circuit for a chosen bandwidth.
This circuit uses the AD5700, the industry’s lowest power and smallest footprint HART®1-compliant IC modem, and the AD5422 16-bit current output and voltage output DAC to form a complete HART-compatible 4-mA to 20-mA solution. An OP184 op amp 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.
This circuit is a complete thermocouple signal-conditioning circuit with cold-junction compensation followed by a 16-bit sigma-delta (Σ-Δ) analog-to-digital converter (ADC). The AD8495 thermocouple amplifier provides a simple, low-cost solution for measuring K-type thermocouple temperatures, including cold-junction compensation. Its fixed-gain instrumentation amplifier scales the small thermocouple voltage to provide a 5 mV/°C output. The amplifier’s high common-mode rejection blocks common-mode noise picked up by the long thermocouple leads. For additional protection, its high-impedance inputs make it easy to add extra filtering. The AD8476 differential amplifier provides the correct signal levels and common-mode voltage to drive the AD7790 16-bit, Σ-Δ ADC, providing a compact, low-cost solution for thermocouple signal conditioning and high-resolution analog-to-digital conversion.
This circuit uses the
AD5700 modem and the
AD5420 16-bit current-output
DAC to form a complete HART-compatible 4-mA to 20-mA solution that adheres
to HART physical layer specifications including analog rate of change and
noise during silence. For many years, 4-mA to 20-mA communication has been
used in process-control instrumentation because it is reliable, robust,
and insensitive to environmental interference over long communication
distances, but, it only allows one-way communication of one process
variable at a time. The highway addressable remote transducer (HART)
standard overcomes this limitation, providing two-way digital
communication along with 4‑mA to 20‑mA analog signaling used by
traditional instrumentation equipment, and enabling remote calibration,
fault interrogation, and transmission of additional process variables.
HART communications modulates a 1-mA peak-to-peak frequency-shift-keyed
(FSK) signal on top of the
This complete, smart, industrial loop-powered field instrument has a 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 in applications such as temperature and pressure control.
This circuit pairs a ADV7391 digital-to-analog video converter with an ADA4432-1 low-cost, low-power, fully integrated video reconstruction filter with output short-to-battery (STB) protection, making it ideal for CVBS video transmission in harsh infotainment environments, such as automotive applications. Although many video DACs can drive video loads directly, it is often beneficial to use a video driver at the output of a video encoder for power savings, filtering, line driving, and overvoltage circuit protection. The video driver, typically configured as an active filter (reconstruction filter), blocks the higher frequency components (above the Nyquist frequency) introduced into the video signal as part of the sampling process, and provides gain to drive the external 75-Ω cable to the video display. In addition, it offers overvoltage protection and hardened ESD tolerance, along with excellent video specifications, low power consumption, and wire diagnostic features.
This circuit is a 20-bit, linear, low noise, precision, unipolar (+10 V) voltage source with a minimum amount of external components. The AD5790 DAC is a 20-bit, unbuffered voltage output DAC that operates from a bipolar supply of up to 33 V. The AD5790 accepts a positive reference input range of 5 V to VDD − 2.5 V, and a negative reference input range of VSS + 2.5 V to 0 V. Both reference inputs are buffered on the chip, and external buffers are not required. The AD5790 offers a relative accuracy specification of ±2 LSB maximum, and operation is guaranteed monotonic with a −1 to +2 LSB maximum DNL specification.
Dual 10-bit nanoDAC Digital-to-Analog Converters include 2-ppm/°C reference
The AD5313R and AD5338R dual, 10-bit nanoDAC® buffered voltage-output DACs include an internal 2.5-V, 2-ppm/°C reference that is enabled by default. A gain-select pin sets the full-scale output to 2.5 V or 5 V. Guaranteed monotonic by design, the DACs exhibit less than 0.1% FSR gain error and 1.5-mV offset error. A power-on reset circuit ensures that the outputs power up to zero scale or midscale and remain at that level until a valid write takes place. The AD5313R includes an SPI-compatible serial interface that operates at clock rates up to 50 MHz and supports readback and daisy-chaining in systems with higher channel counts; the AD5338R includes an SPI-compatible serial interface that operates at clock rates up to 400 kHz. Operating on a 2.7-V to 5.5-V supply, the devices are compatible with 1.8-V to 5.5-V logic. They draw 1.1 mA when the internal reference is on and 0.59 mA when it is off. A per-channel power-down mode reduces the supply current to 1 µA. Specified from –40°C to +105°C, the AD5313R/38R are available in 16-lead TSSOP and 3-mm × 3-mm LFCSP packages, and are priced at $1.96 in 1000s.
14-bit, 32-channel DAC with programmable full-scale output-voltage of 50 V to 200 V
AD5535B denseDAC® high-voltage
D/A converter integrates 32
14-bit DACs and 32 high-voltage amplifiers. Its full-scale output voltage
range can be programmed from 50 V to 200 V by changing the reference from 1
V to 4 V, making it ideal for deflection and control of mirrors in optical
MEMS (micro-electromechanical systems)—and for use in optical crosspoint
switches, micropositioning applications using piezoelectric actuators, and
automotive level-setting applications. Data is written to the selected DAC
register via a 3-wire SPI-compatible interface that operates at clock rates
up to 30 MHz. Guaranteed monotonic, the DACs have 550-μA drive capability.
An on-chip thermal diode facilitates temperature monitoring. The AD5535B
operates with a ±4.75-V to ±5.25-V analog supply, 2.7-V to 5.25-V digital
supply, and 215-V high-voltage supply. Specified from –10°C to 85°C, it is
available in a
Quad, 12-/16-bit nanoDAC+ Digital-to-Analog Converters
AD5687/AD5689 dual, 12-/16-bit nanoDAC+TM
buffered voltage-output DACs feature ±1-/±2-LSB max INL, 0.1% max gain
Dual, 12-/16-bit nanoDAC+ Digital-to-Analog Converters include 2-ppm/°C reference
AD5687R/AD5689R dual, 12-/16-bit nanoDAC+TM
buffered voltage-output DACs include an internal 2.5-V, 2-ppm/°C reference
that is enabled by default. A gain-select pin sets the full-scale output to
2.5 V or 5 V, and a power-on
reset circuit ensures that the outputs power up to zero scale or midscale
and remain at that level until a valid write takes place. Guaranteed
monotonic by design, the DACs feature ±1-/±2-LSB max INL, 0.1% max gain
error, and 1.5-mV max offset error. The SPI-compatible serial interface,
which operates at clock rates up to 50 MHz, supports readback and
daisy-chaining in systems with higher channel counts. Operating on a 2.7-V
to 5.5-V supply, the devices are compatible with 1.8-V to 5.5-V logic. They
draw 1.1 mA in normal mode and 1 µA in power-down mode.
Specified from –40°C to +105°C, the AD5687R/89R are available in 16-lead
Dual, 12-bit nanoDAC+ Digital-to-Analog Converter includes 2-ppm/°C reference
The AD5697R dual, 12-bit nanoDAC+TM
buffered voltage-output DAC includes an internal 2.5-V, 2-ppm/°C reference
that is enabled by default. A gain-select pin sets the full-scale output to
2.5 V or 5 V, and a power-on
reset circuit ensures that the output powers up to zero scale or midscale
and remains at that level until a valid write takes place. Guaranteed
monotonic by design, the DACs features ±1-LSB max INL, 0.1% max gain error,
and 1.5-mV max offset error. The I2C-compatible serial interface
operates at clock rates up to 400 kHz. Operating on a 2.7-V to 5.5-V supply
and compatible with 1.8-V to 5.5-V logic, the AD5697R draws 1.1 mA in
normal mode and 1 µA in power-down mode. Specified from –40°C to
+105°C, it is available in 16-lead TSSOP and
High-performance Isolated Error Amplifier offers alternative to optocouplers and shunt regulators
The ADuM3190 isolated error amplifier is ideal for linear feedback power supplies with primary side controllers. Its 400-kHz bandwidth, 0.5% typical initial accuracy at 25°C, and 1% total accuracy over temperature provides manufacturers of ac-to-dc and dc-to-dc power supplies, including those that are DOSA (Distributed-power Open Standards Alliance)-compliant, with a significant upgrade in speed and operating temperature range, as well as a 5× improvement in transient response. Designed with ADI’s iCoupler® digital isolation technology, it eliminates the CTR (current-transfer ratio) of optocouplers that degrades over lifetime and limits operation to 85˚C. The ADuM3190 includes a high-accuracy 1.225-V reference and a wideband operational amplifier that can be used to set up a variety of commonly used power supply loop compensation techniques. Specified from –40°C to +125°C, it is available in a 16-lead QSOP package and priced at $1.04 in 1000s.
Digital Controller for isolated power supplies
ADP1046A secondary-side controller for
switch-mode power supplies integrates all of the functions required to
control isolated ac-to-dc or dc-to-dc converters, including: current-,
voltage-, and temperature sensing; loop-filter compensation, PWM generation,
current sharing, redundant OrFET control, housekeeping, I2C
interface, calibration, and trimming. Its robust design provides
programmable overcurrent protection, undervoltage lockout, overvoltage
protection, overtemperature protection, and hot-swap control; and its
flexibility and minimal requirement for external components greatly shortens
design time. The on-chip EEPROM is used for programming the loop filter, PWM
timing, inrush current, soft start timing, and sequencing. A graphical user
interface eases filter design and configuration. Operating from a single
3.0-V to 3.6-V supply, the ADP1046A draws 20 mA in normal mode and
100 µA in shutdown mode. Specified from –40°C to
Low-power 14-bit, 180-MSPS Digital-to-Analog Converter and Waveform Generator
The AD9102 TxDAC® digital-to-analog converter combines a high-performance DAC with on-chip pattern memory for complex waveform generation using a direct digital synthesizer (DDS). The DDS generates a 14-bit sine wave at up to 180 MHz for use as a master clock. A 24-bit tuning word enables 10.8-Hz frequency resolution; an SRAM can store waveforms, modulation patterns, and DDS tuning words; and a state machine programs the period and start delay within the period. Control and configuration data is loaded via an SPI-compatible interface. Operating on a single 1.8-V supply, the AD9102 dissipates 51 mW at 180 MSPS and 1.49 mW in power-down mode. Available in a 32‑lead LFCSP package, it is specified from –40°C to +85°C and priced at $12.35 in 1000s.
Dual-channel Digital Isolator with DC-to-DC Converter
The ADuM6210, ADuM6211, and ADuM6212 dual-channel digital isolators include an isoPower® integrated, isolated dc-to-dc converter. Based on iCoupler® technology, the dc-to-dc converter provides regulated, isolated power, adjustable between 3.15 V and 5.25 V. Input supply voltages can range from slightly below the required output to significantly higher, eliminating the need for a separate, isolated dc-to-dc converter in low power, isolated designs. The iCoupler chip-scale transformer technology is used to isolate the logic signals and for the magnetic components of the dc-to-dc converter. The result is a small form factor, total isolation solution. The three models provide two independent isolation channels in a variety of channel configurations and data rates. Available in 20-lead SSOP packages with 5.3mm creepage, the ADuM621x are specified from –40°C to +105°C and priced from $3.36 in 1000s.
Maithil Pachchigar, Complete Sensor-to-Bits Solution Simplifies Industrial Data-Acquisition System Design, Analog Dialogue, 2013-04-01
Chau Tran, Marco Ablao, and Sherwin Gatchalian, Differential input to differential output amplifiers equal high temp solution, EE Times, 2013-02-06
Chau Tran, Current transmitter operates at extremely high temperatures, EE Times, 2013-01-23
C. Goodall, S. Carmichael, and B. Scannell, The Battle Between MEMS and FOGs for Precision Guidance, EDN, 2013-01-21
Chau Tran and David Karpaty, Simple circuit measures RMS value of AC power line, EE Times, 2012-11-08
Brian Kennedy, Implementing an Isolated Half-Bridge Gate Driver, Analog Dialogue, 2012-11-05
Reza Moghimi, Key benefits of input over-voltage protected op amps in systems, EDN, 2012-10-21
Bill Slattery, Domains of Isolation, Electronic Specifier Design, 2012-10-01
Tracey Johnson, HART Communication Networks Are Improved by Small, Flexible, Low-Power Modem ICs, Analog Dialogue, 2012-10-03
David Krakauer, Reduce size and cost with integrated industrial interface digital isolators, EDN, 2012-09-24
Maurice O’Brien, Multichannel regulators enable smaller and more reliable embedded power solutions, Electronics Components World, 2012-09-11
Martin Murnane, Isolation Technology Helps Integrate Solar Photovoltaic Systems onto the Smart Grid, Analog Dialogue, 2012-09-04
Designing Robust Isolated RS-232 Data Interfaces for Harsh Industrial
Applications, Electronic Specifier Design,
Maurice O’Brien, Designing Robust Isolated RS-232 Data Interfaces for Harsh Industrial Applications, Analog Dialogue, 2012-08-01
Michael Long, Processors support the demands of video analysis within the security & surveillance market, Connecting Industry, 2012-07-31
Mark Looney, Analyzing Frequency Response of Inertial MEMS in Stabilization Systems, RF Globalnet, 2012-07-25
Mark Looney, Analysing frequency response of inertial MEMS in stabilisation systems, New Electronics, 2012-07-10
Luis Orozco, Digital Isolators Simplify Design and Ensure System Reliability, EDN, 2012-07-09
Mark Looney, Analyzing Frequency Response of Inertial MEMS in Stabilization Systems, Analog Dialogue, 2012-07-02
Marcus O'Sullivan, Optimize High-Current Sensing Accuracy by Improving Pad Layout of Low-Value Shunt Resistors, Analog Dialogue, 2012-06-04
Petre Minciunescu and Brian Kennedy, Digital Isolation in Smart Energy Metering Applications, EDN Europe, 2012-06-01
Isolated Interface Solutions for Industrial Sensor and Monitoring Applications (German) - This webcast reviews designs in which isolation is needed to protect personnel and equipment from harsh electrical environments. The presentation will detail interface power requirements and approaches for achieving design objectives. Topics will include performance tradeoffs for various approaches and applicable safety certifications for interface components.
Guarding RS485 Communication Networks from Harmful EMC Events - This webcast will discuss industry’s first EMC compliant RS-485 interface design tool co-developed by Analog Devices and Bourns that provides up to Level 4 protection levels for IEC61000-4-2 ESD, IEC61000-4-4 EFT and IEC61000-4-5 surge. This webcast describes each of these transient types, and presents and demonstrates three different EMC compliant solutions for three different cost/protection levels on RS-485 communication ports.
Low Power Smart Transmitters Design - This webcast will explore some of the key trends in modern field instrument design, the most complex of which are high performance, low power, and increased diagnostic capabilities. It will examine the power consumption challenges of loop-powered smart transmitters, and give an example of a full signal chain solution that has been developed by Analog Devices and registered by the HART Communication Foundation.
Isolated Interface Solutions for Industrial Sensor and Monitoring Applications - This webcast reviews designs in which isolation is needed to protect personnel and equipment from harsh electrical and mechanical environments. Presentation will detail interface power requirements and approaches for achieving design objectives. Topics will include performance tradeoffs for various approaches and applicable safety certifications for interface components.
Fundamentals of Energy Metering - This webinar will explore system architectures for 3‑phase electricity meters, focusing on various current sensors and considerations for the analog front end, power supply and data isolation, metrology computations and system performance. Current transformers (CTs), di/dt (Rogowski coils), and shunt resistors will be discussed.
The Fundamentals of Voltage References and Current Sensing - This webcast will discuss voltage references and how they are used in circuit design. It will also cover and compare reference designs, specifications, reference alternatives, and application ideas such as negative references, then present how currents are handled, measured, and generated in system design.
Designing for Field Instruments in Industrial Automation - This webcast will provide an overview of field instrumentation with a focus on specifics and trends. Using a 4- mA to 20-mA loop-powered pressure transmitter as an example, the webcast will present details of system requirements, map them into the system architecture and circuit diagram, discuss the typical design challenges, and how today’s ICs provide solutions to those challenges.
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