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应用笔记

零漂移放大器实现精密信号调理应用

AN-1114:最低噪声的零漂移放大器提供5.6 nV/√Hz电压噪声密度

传感器产生的输出电压通常很小,需要通过具有高增益和精密直流性能的信号调理电路进行调理。遗憾的是,放大器的失调电压、漂移和1/f噪声会导致误差,尤其是对于低频、低电平电压测量,因此降低失调电压和漂移并消除1/f噪声对于实现最佳信号调理至关重要。零漂移放大器实现了超低失调电压和漂移、高开环增益、高电源抑制、高共模抑制以及零1/f噪声,能够给精密应用设计人员带来便利。这篇8页的应用笔记探讨零漂移放大器AD4528-1的架构、特征和设计考虑。

在温度超出额定范围的情况下提高测量精度

AN-1087:使用AD8495/AD8496/AD8497时的热电偶线性化

AD8494/AD8495/AD8496/AD8497热电偶放大器可解决有关热电偶使用的许多困难,为热电偶温度测量提供一种简单的低成本解决方案。这些器件集仪表放大器和温度传感器于一体,能够放大很小的热电偶电压并执行冷结补偿。对于0°C至100°C的环境温度和−35°C至565°C的测量温度,AD849x的测量精度在±2°C以内。这篇4页的应用笔记介绍了在工作或测量温度超出额定范围的情况下实现更高精度的方法。

可编程时序控制器控制线路卡和刀片卡的上电

AN-1086:ADM106x的热插拔应用

超级时序控制器系列ADM106x super sequencers®能够精确监控多个输入轨,ADM1062至ADM1067有10个专用输入引脚,ADM1068和ADM1069有8个专用输入引脚。各引脚具有两个内部可编程比较器电路。可以将这些电路编程为仅欠压、仅过压或欠压/过压模式,从而针对各个受监控的电源设置跳变点。ADM106x内置一个电源仲裁器,它能自动从其输入电源引脚上的最高电压轨为器件供电。这些器件通常用于电信基础设施(中央交换局和基站)线路卡和服务器刀片卡等需要热插拔到带电背板的应用。在线路卡应用中,ADM106x可能需要是电路板上第一个上电的器件,因为它必须监控电路板上的输入电源;如果电源在设定限值以内,则向热插拔控制器提供一个使能信号,从而允许电路板的主要部分上电。这篇2页的应用笔记描述卡片在带电背板中热插拔的情况下,ADM106x的输入电源接通时必须考虑的设计要求。

Σ-Δ型ADC用于多通道应用

AN-1084:通道切换:AD7190、AD7192、AD7193、AD7194、AD7195

Σ-Δ型ADC的特性一般用输出数据速率来规定,输出数据速率是指当一个通道被选中且ADC连续进行转换时的转换速率。在数据采集系统等多通道应用中,每个通道被依次选择,同时针对所选通道执行转换。这些应用中的转换速率与单通道系统的转换速率并不相同。这篇8页的应用笔记描述AD7190、AD7192、AD7193、AD7194和AD7195 Σ-Δ ADC所采用的通道切换程序。

基于ADE78xx电表的快速校准程序

AN-1076:基于ADE7878的三相电表

3相电表可用ADE7878三相多功能电能计量IC构建,以电流变压器(CT)检测相位和零线电流,以电阻分压器检测相位电压。微控制器通过I2C或SPI通信管理ADE78xx。这篇12页的应用笔记介绍校准该电表的过程。这款电表使用3相、4线配置,内置三个电压传感器,不过校准流程也可用于其他配置。

使用ADP1870/ADP1872的高效率升压/降压DC-DC转换器

AN-1075:使用ADP1870/ADP1872的同步反向SEPIC为同相降压/升压应用提供高效率

许多市场对高效同相DC-DC转换器的要求越来越高,不但能在降压或升压模式下工作,还可将输入电压减小或增大至所需的调节电压,并且具有极低的成本和功率损耗,元件数量最少。反向单端初级电感转换器(SEPIC)也称为Zeta转换器,具有许多非常适合此项功能的特性。这篇12页的应用笔记分析采用ADP1870/ADP1872同步开关控制器的操作和实施方案,说明适合此应用的一些特性。

Σ-Δ型ADC为多路复用应用提供零延迟模式

AN-1069:AD7190、AD7192、AD7193、AD7194和AD7195的零延迟模式

AD7190/92/93/94/95超低噪声、24位、Σ-Δ型PGA模数转换器内置可按多种方式配置的数字滤波器,采用其中一种配置工作时不存在一般Σ-Δ型ADC常有的建立时间延迟问题。这篇4页的应用笔记介绍此特性,并与这些ADC中同时提供的传统滤波进行比较。

为工业过程控制应用中的4mA至20mA电流环路增加数字通信功能

AN-1065:AD5420的HART通信兼容配置

高速通道可寻址远程传感器(HART)标准的发展为4mA至20mA通信开启了新的可能。HART数字双向通信兼容4mA至20mA电流环路。在4mA至20mA模拟电流信号上调制一个1mA峰峰值频移键控(FSK)信号。根据BELL 202通信标准,所用的两个频率为代表逻辑1的1200 Hz和代表逻辑0的2200 Hz。AD5420是一款16位数模转换器,具有4mA至20mA输出和输入,可接受HART调制解调器的输出。HART调制解调器的输出经过衰减后,交流耦合至AD5420;这导致调制解调器输出在4mA至20mA模拟电流上进行调制,而不会影响该电流的直流电平。这篇4页的应用笔记介绍AD5420如何与微控制器和HART调制解调器接口,使HART支持PLC和DCS系统常用的4mA至20mA电流输出。

增强EMC保护,同时保持电容数字转换精度

AN-1055:AD7746的EMC保护

AD7746电容数字转换器(CDC)可直接测量浮地电容传感器的电容,即传感器直接连到AD7746输入引脚。电磁干扰会扭曲容性传感器周围的电场,从而改变电容测量结果。可以通过外部滤波保护AD7150,使之不受电磁干扰影响,但在信号路径中增加滤波器会降低转换精度。这篇20页的应用笔记讨论AD7746引脚上的外部滤波器可以实现的EMC性能,以及滤波器对AD7746精度的影响。

阻抗转换器测量未知阻抗

AN-1053:AD5933评估板测量示例

这篇5页的应用笔记详细说明如何设置AD5933阻抗转换器的评估板,以及如何测量板上15 pF电容的阻抗。AD5933数据手册提供了更多信息,使用评估板时应加以参考。

实验室电路

采用低压(3 V)电源供电的高压(30 V) DAC产生用于天线和滤波器的调谐信号(CN0193)

本电路可产生高压信号,用于控制BST(钛酸钡锶)电容的电容量。BST常用于调谐天线阵列和可调滤波器。此类应用需要一个方便、紧凑、低成本的电路来产生高压电源,仅为了该功能添加独立电源通常并不实用。采用ADP1613升压转换器和AD5504 30 V/60 V DAC可满足上述要求。

用于AD2S1210旋变数字参考信号输出的高电流驱动器(CN0192)

RDC与旋转传感器配合使用,以便检测电机轴的位置和转速。在这种应用中,旋变器利用正弦波参考信号进行激励。初级绕组上的旋变器激励参考信号转换为两个正弦差分输出信号:正弦和余弦。正弦和余弦信号的幅度取决于实际的旋变器位置、旋变器转换比和激励信号幅度。RDC同步采样两个输入信号,以便向数字引擎(即所谓Type II跟踪环路)提供数字化数据。Type II跟踪环路负责计算位置和速度。

20位、线性、低噪声、精密、双极性±10V直流电压源(CN0191)

本电路提供20位可编程电压,其输出范围为−10 V至+10 V,同时积分非线性为±1 LSB、微分非线性为±1 LSB,并且具有低噪声特性。该电路的数字输入采用串行输入并与标准SPI、QSPI™、MICROWIRE®和DSP接口标准兼容。对于高精度应用,该电路可以提供高精度和低噪声性能。

相位相干FSK调制器(CN0186)

标准的单通道直接数字频率合成器(DDS)不会以相位相干形式在不同频率之间切换。根据设计,DDS频率转换具有相位连续性,而不相干。不过,本电路展示了如何配置AD9958/AD9959多通道DDS,通过叠加多通道DDS输出实现稳定的相位相干FSK(频移键控)调制器。

使用故障保护CMOS开关的关断保护数据采集信号链(CN0165)

采用远程信号源时,发生损害故障的可能性更大。过压状况、连接欠佳引起的瞬变电压和电源故障可能会造成重大损坏,导致高昂的维修成本。本电路针对失电和过压状况提供一种低成本、可靠的保护解决方案。

新产品简介

June 2011

Precision 3-axis Inclinometer/Accelerometer

adis16210The ADIS16210 digital inclinometer/accelerometer combines a 3-axis accelerometer with an embedded signal processor to provide precise measurements of roll- and pitch angles. An SPI-compatible serial interface communicates commands, and inclination-, acceleration-, on-chip temperature-, and power-supply data. The inclinometer features ±0.1° relative accuracy over a ±180° measurement range for roll- and pitch axes and a ±90° measurement range for the gravity axis; the accelerometer provides a ±1.7-g measurement range with ±0.05° axis-to-axis alignment error. Sample rate, digital filtering, power-management mode, and offset/null calibrations are all fully user configurable. Programmable alarms can report out-of-limit conditions, and the self-test feature can monitor operation of the sensor’s mechanical structure. Operating on a single 3.0-V to 3.6-V supply, the ADIS16210 draws 18 mA in normal mode and 230 μA in sleep mode. Available in a 15-lead, 15-mm × 24-mm × 15-mm compact module, it is specified from –40°C to 125°C and priced at $97.00 in 1000s.

Ten-Degrees-of-Freedom Inertial Sensor

adis16407The ADIS16407 complete “10-degrees-of-freedom” inertial sensing system combines a 3-axis gyroscope—with ±75°/s, ±150°/s, and ±300°/s range settings; a 3-axis accelerometer—with ±18-g range; a 3-axis magnetometer—with ±2.5-gauss range; and a barometer—with 10-mbar to 1200-mbar range; plus a local temperature sensor, a 12-bit ADC, and a 12-bit DAC. The device is fully calibrated for sensitivity, bias, axial alignment, and linear acceleration over .the –40°C to +85°C temperature range. Functionally complete, it includes programmable self-test, power management, and alarms. All data and commands are communicated via an SPI-compatible serial interface. Operating on a single 4.75-V to 5.25-V supply, the ADIS16407 consumes 70 mA in normal mode and 1.4 mA in sleep mode. Available in a 24-lead, 23‑mm × 23‑mm × 23‑mm compact module, it is specified from –40°C to +105°C and priced at $444.00 in 1000s.

Vibration-rejecting yaw-rate Gyroscope has ?50?s measurement range

adxrs642The ADXRS642 angular rate sensor uses an advanced, differential, quad-sensor design to reject the influence of shock and vibration, providing improved sensing in harsh environments. The output voltage, proportional to the angular rate about the Z‑axis, is ratiometric to an external reference. Bandwidth, from 0.01 Hz to 2 kHz, is set by an external capacitor; and the ±250°/s measurement range can be extended to ±450°/s by connecting an external resistor. Two digital self-test inputs excite the sensor electromechanically to test proper operation of the sensor and signal-conditioning circuits. A temperature output is available to facilitate compensation. Designed for industrial applications, inertial measurement units, and platform stabilization, the device can survive 10,000-g powered shocks. Operating with a single 4.75-V to 5.25-V supply, the ADXRS642 draws 3.5 mA. Available in a 32-ball CBGA package, it is specified from –40°C to +105°C and priced at $41.85 in 1000s.

Instrumentation Amplifier features 1-nV/rt-Hz input noise

ad8429The AD8429 ultralow-noise instrumentation amplifier is ideal for measuring extremely small signals over a wide temperature range. Excellent for measuring tiny signals, the amplifier features industry-leading 1-nV/rt-Hz input noise and 50-µV max input offset voltage specifications.. Its common-mode rejection (CMR) increases from 80 dB at G=1 to 140 dB at G=1000, offering high rejection when it is most needed; and its high-performance pin-out allows CMR to be guaranteed from dc to 5 kHz. Its current-feedback architecture provides wide bandwidth and fast settling times: 15 MHz and 0.75 µs at G=1, 4 MHz and 0.65 µs at G=10, 1.2 MHz and 0.85 µs at G=100, and 0.15 MHz and 5 µs at G=1000. Gain is set from 1 to 10,000 with a single external resistor. A reference pin allows the output voltage to be offset. Operating on ±4-V to ±18-V supplies, the AD8429 draws 9 mA max over temperature. Specified from –40°C to +125°C, it is available in an 8-lead SOIC package and priced from $3.50 in 1000s.

600-MHz Pin Electronics IC includes dual DCL with PPMU, VHH drive, and DACs

adate318The ADATE318 single-chip automatic-test-equipment (ATE) solution performs the pin-electronics functions of driver, comparator, and active load (DCL)—at speeds of up to 600 MHz. It also provides a per-pin parametric measurement unit (PPMU), dc level-setting DACs, VHH drive capability, and an on-chip calibration engine. The four-quadrant PPMU can force or measure voltage or current—and measure voltage or current—on a per-pin basis. The dual device can be used in two single-ended drive/receive channels or a single differential channel. The proprietary driver features three active states: logic high, logic low, and terminate mode. Its high-impedance inhibit mode and integrated dynamic clamps facilitate high-speed active termination; and its –1.5-V to +6.5-V voltage range accommodates a wide variety of test devices. The active load can source/sink ±25 mA. The PPMU provides ±2-μA, ±10-μA, ±100-μA, ±1-mA, and ±40-mA force/measure current ranges with –2-V to +6.5-V force/measure voltage compliance. A high-voltage buffer can source voltages up to 13.5 V for flash memory testing. High-speed window- and differential comparators facilitate functional testing. On-chip 16-bit DACs set the dc levels for the DCL and PPMU. Available in an 84-lead LFCSP package, the ADATE318 is specified from 25°C to 70°C and priced at $42.08 in 1000s.

Lithium-ion Battery-Monitoring System

ad7280aThe AD7280Alithium-ion battery-monitoring system contains all of the functions required for monitoring battery stacks in hybrid electric vehicles, power tools, and power-supply backups. Multiplexing six voltage inputs and six temperature inputs into a 12-bit, 1-Msps ADC, it monitors up to six cells. Functionally complete, it includes a 2.5-V, ±3-ppm/°C voltage reference, channel sequencer, alert function, cell-balancing interface, and self-test feature, which applies a known voltage to the ADC inputs. Its daisy-chain interface allows up to eight devices to be stacked without the need for individual device isolation, enabling conversion of up to 48 cell voltages within 7 μs. Operating with an 8‑V to 30-V supply, the AD7280A dissipates 170 mW during conversion, 75 mW in software power-down mode, and 54 µW in full power-down mode. Available in a 48-lead LQFP package, it is automotive qualified to AECQ100, specified from –40°C to +105°C, and priced at $4.33 in 1000s.

8-channel Data-Acquisition System includes 18-bit, simultaneous-sampling ADC

ad7608The AD7608 data-acquisition system comprises an 8-channel analog front-end, an 8:1 multiplexer, an 18-bit successive-approximation ADC, a precision 2.5-V reference—and reference buffer—a flexible digital filter, and a host of control interfaces and power-management peripherals. Each channel—which accepts true bipolar inputs with ±5-V or ±10-V full-scale range—includes analog input-protection clamps, a fully differential amplifier, a second-order anti-aliasing filter, and a track-and-hold amplifier. All eight channels—or two groups of four channels—can be sampled simultaneously. Operating with a 4.75-V to 5.25-V supply, the AD7608 dissipates 100 mW at 200 ksps, 25 mW in standby mode, and 10 µW in shutdown mode. Available in a 64-lead LQFP package, it is specified from –40°C to +85°C and priced at $20.50 in 1000s.

Quad 16-bit DAC provides voltage and current outputs, HART connectivity

ad5755-1The AD5755-1four-channel 16-bit digital-to-analog converter provides voltage and current outputs for programmable logic controllers (PLC), distributed control systems (DCS), and other industrial process-control applications. Dynamic power control regulates the voltage on the output driver, minimizing power dissipation with low-value load resistors—and easing thermal management. Each channel can be configured to provide a voltage output, with 0–5 V, 0–10 V, ±5 V, or ±10 V full-scale range and ±0.04% total unadjusted error (TUE)—or a current output, with 0‑20 mA, 4‑20 mA, or 0‑24 mA full-scale range and ±0.05% TUE. Offset and gain can be individually programmed for each channel. The devices can be used with the on-chip 5‑V, ±5-ppm/°C reference or an external reference. Dedicated inputs enable the device to support HART communications. Operating with +5-V and ±15-V supplies, the AD5755-1 dissipates 173 mW. Available in a 64-lead LFCSP package, it is specified from –40°C to +105°C and priced at $15.88 in 1000s.

Quad 16-bit DAC provides current output, HART connectivity

ad5757The AD5757four-channel 16-bit digital-to-analog converter provides a current output for programmable logic controllers (PLC), distributed control systems (DCS), and other industrial process-control applications. Dynamic power control regulates the voltage on the output driver, minimizing power dissipation with low-value load resistors and easing thermal management. Each channel can be configured to provide a 0‑20 mA, 4‑20 mA, or 0‑24 mA full-scale range and ±0.05% TUE. Offset and gain can be individually programmed for each channel. The devices can be used with the on-chip 5-V, ±5‑ppm/°C reference or an external reference. Dedicated inputs enable the device to support HART communications. Operating with +5-V and ±15-V supplies, the AD5757 dissipates 155 mW. Available in a 64-lead LFCSP package, it is specified from –40°C to +105°C and priced at $10.85 in 1000s.

SHARC Processors

adsp-21478/79The ADSP-21478 and ADSP-21479fourth-generation low-power SHARC® processors offer increased performance, hardware-based filter accelerators, audio- and application-focused peripherals, and up to 5 Mbits of SRAM, making them ideal for professional and automotive audio applications. Their single-instruction, multiple-data (SIMD) core supports 32-bit fixed-point and 32-/40-bit floating-point arithmetic formats—performing up to 1800 MFLOPS with a 300-MHz clock. The variable instruction-set architecture (VISA) allows code to be decreased by 20% to 30%, increasing the available memory. Application-specific peripherals simplify hardware design, minimize design risks, and reduce time to market. The software-programmable signal routing unit (SRU) enables flexible routing of digital applications interface (DAI) blocks. Peripherals connected through the SRU include serial ports, SPI ports, S/PDIF transceiver, and an 8-channel asynchronous sample-rate-converter block. The digital peripheral interface (DPI) includes a UART and a two-wire interface. FIR, IIR, and FFT accelerators increase the total system performance. The DMA controller can transfer data from the serial ports to external 16-bit SDR SDRAMs through a glueless interface. All SHARC processors are pin- and code compatible. Specified from 0°C to +70°C (K-grade) or –40°C to +85°C (B-grade), the ADSP-21478/79 are available in 100-lead LQFP and 196-ball CSP-BGA packages and priced from $7.99 in 1000s.

Blackfin Embedded Processor

adsp-bf592The ADSP-BF592Blackfin processors—optimized for cost-sensitive industrial, automotive, and medical applications—combine the multimedia signal-processing power of a single-instruction, multiple-data (SIMD) DSP with the control capabilities of a RISC microcontroller. With two 16-bit MACs, two 40-bit ALUs, four 8-bit video ALUs, and 132K bytes of core-addressable memory, they operate at up to 400 MHz. 64K bytes of factory-programmed instruction ROM contains VDK RTOS and C-runtime libraries. Peripherals include four timer/counters (three with PWM); two full-duplex synchronous serial ports (SPORTs) that support eight channels of I2S stereo audio; two SPI ports; one UART with IrDA support; a parallel peripheral interface (PPI) that supports ITU-R 656 video formats; a two-wire interface (TWI) controller; nine peripheral DMAs; two memory-to-memory DMA channels, an event handler, 32 GPIOs, a JTAG debugging interface, and a PLL. Specified from 0°C to +70°C (K-grade) or –40°C to +85°C (B-grade), the ADSP-BF592 is available in a 64-lead LFCSP package and priced from $3.56 in 1000s.

Super Sequencer with margining control and nonvolatile fault recording

adm1169The ADM1169super sequencer® configurable power-supply supervisor monitors and sequences up to eight supplies in multiple-supply systems. Eight programmable inputs can be used for monitoring overvoltage, undervoltage, or out-of-window faults: one can be used for a supply voltage up to 14.4 V; three can be used for supply voltages up to 6 V; and four can be used for supply voltages between 0.573 V and 1.375 V—or digital signals, such as reset, power good, or fault. Eight programmable outputs can enable supplies individually under the control of the sequencing engine. Six of these outputs can provide a 12-V gate drive to N‑channel FETs. The sequencing engine provides up to 63 states, enabling flexible sequencing of the outputs based upon the condition of the inputs. Nonvolatile EEPROM can store user-defined data or, when controlled by the sequencing engine, it can automatically log supply faults or system input faults. A 12-bit ADC measures supervised voltages and on-chip or remote temperatures, and four 8-bit DACs implement closed-loop power-supply margining. For improved redundancy, the device is powered from the highest of the four voltages on the voltage-monitor inputs. Operating with a 3-V to 14.4-V supply; the ADM1169 draws 4.2 mA. Available in 32‑lead LQFP and 40-lead LFCSP packages, it is specified from –40°C to +85°C and priced at $6.49 in 1000s.

Hot-Swap Controller and Digital Power/Energy Monitor

adm1276The ADM1276hot-swap controller allows circuit boards to be inserted into or removed from a live backplane without damage. The on-chip 12-bit ADC monitors the supply voltage, load current, and output voltage with ±0.7% accuracy, and communicates the results via a PMBus interface. The load current is detected with an on-chip current-sense amplifier, which measures the voltage across a sense resistor in the power path. The device controls supply voltages in the 2-V to 20-V range by modulating the gate voltage on an external N-channel FET pass device. The current limit is set by limiting the voltage across the sense resistor to a programmable value between 5 mV and 25 mV. Overvoltage and undervoltage protection thresholds are programmed with external resistors; a power-good signal indicates valid output voltage. Available in a 20-lead LFCSP package, it is specified from –40°C to +85°C and priced from $5.29 in 1000s.

Dual-output Low-Dropout Regulator drives 300-mA loads

adp223The ADP223dual adjustable-output low-dropout regulator (LDO) can be configured to provide output voltages between 0.5 V and 5 V by adding two resistors per channel. It features ±1% accuracy, 76-dB power-supply rejection, 27-µV rms noise, 300‑mA drive capability, and 120-mV dropout voltage, making it ideal for battery-powered applications with demanding requirements for performance and board area. Two active-high inputs independently enable the two outputs, which can be connected in parallel for increased output current. The device offers overcurrent and thermal protection. Operating with a 2.5-V to 5.5-V supply, the ADP223 consumes 180 µA with a 300-mA load, 65 µA with no load, and 0.1 µA in shutdown mode. Available in an 8-lead, 2-mm × 2-mm LFCSP package, it is specified from –40°C to +125°C and priced at $0.49 in 1000s.

Micro-PMU includes 800-mA buck regulator, 300-mA LDO, supervisory functions

adp5043The ADP5043micro-power-management unit (µPMU) combines a high-performance 1.5-V, 800-mA buck regulator and a 3.3-V, 300-mA low-dropout regulator (LDO). A supervisory circuit monitors voltage levels and code execution using a watchdog timer—and provides reset signals—increasing system reliability in microprocessor-based systems. If not asserted within the specified time period, a second watchdog timer power cycles the µPMU output voltages to provide a full hardware reset. The buck converter can operate in forced pulse-width modulation (PWM) mode for lowest ripple, or can automatically switch between PWM mode and power-save mode to maximize efficiency at light loads. The LDO specifies 4-mV dropout with a 10-mA load, and 60-mV dropout with a 200-mA load. The buck regulator’s 2.3-V to 5.5-V input range allows the use of standard power sources, including lithium-, alkaline-, and NiMH cells and batteries. The LDO operates from a 1.7-V to 5.5-V input voltage. Available in a 20-lead, LFCSP package, the ADP5043 is specified from –40°C to +125°C and priced at $1.79 in 1000s.

Low-power Programmable Waveform Generator

ad9837The AD9837 low-power programmable waveform generator produces sine, triangular, and square wave outputs for sensing, actuation, and time-domain reflectometry (TDR). The output frequency and phase are software programmable, allowing easy tuning. The 28-bit frequency registers enable 0.06-Hz resolution with a16-MHz clock and 0.02-Hz resolution with a 5-MHz clock. Data is written via a 3-wire DSP- and microcontroller compatible serial interface that clocks at up to 40 MHz. Operating with a single 2.3-V to 5.5-V supply, the AD9837 draws 3.7 mA in normal mode and 0.5 mA in sleep mode. Available in a 10-lead LFCSP package, it is specified from –40°C to +125°C and priced from $1.65 in 1000s.

Low-power Complete DDS

ad9838The AD9838low-power complete DDS produces high-performance sine and triangular outputs; and an on-chip comparator produces a low-jitter square wave output for clock generation. The 28‑bit frequency registers enable 0.06-Hz resolution with a 16-MHz clock and 0.02-Hz resolution with a 5-MHz clock. Phase- and frequency modulation are configured via registers using software or pin selection. Data is written via a 3-wire serial interface that clocks at up to 40 MHz. Operating with a single 2.3-V to 5.5-V supply, the AD9838 draws 3.7 mA in normal mode and 0.4 mA in sleep mode. Available in a 20-lead LFCSP package, it is specified from –40°C to +125°C and priced from $2.10 in 1000s.

High-voltage, latch-up proof, quad SPST CMOS Switches

adg5212/13The ADG5212 and ADG5213quad SPST CMOS switches feature 160-Ω on-resistance with 2-Ω channel-to-channel match and 38-Ω variation over a ±10-V signal range. Their 48-V maximum supply-voltage rating and guaranteed latch-up protection make them ideal for high-voltage applications in industrial, automotive, and other harsh, latch-up prone environments. Capable of handling signals from rail to rail, the switches conduct equally well in both directions. Their dynamic specifications include 0.07-pC charge injection, 3-pF source capacitance, 175-ns switching speed, and 435-MHz bandwidth. The ultralow capacitance and charge injection make them ideal for fast, low-glitch sample-and-holds, while the wide bandwidth and fast switching speed make them well-suited for switching video signals. The ADG5212 comprises four switches that are closed with a logic-1 input; the ADG5213 comprises two switches that are closed with a logic-1 input and two switches that are open with a logic-1 input. Break-before-make switching action makes this device useful in multiplexer applications. The digital inputs are compatible with 3-V logic. Fully specified with +12-V, +36-V, ±15-V, and ±20-V supplies, the ADG5212/13 consume 1.35 mW. Available in 16-lead TSSOP packages, they are specified from –40°C to +125°C and priced at $2.18 in 1000s.

2011年5月

超级时序控制器监控8个电源,具有非易失性故障记录功能

adm1168The ADM1168Super Sequencer®可配置电源监控器可以对多电源系统中的多达8个电源进行监控和时序控制。8路可编程输入可用来监控过压、欠压或超出窗口故障:一路用来监控高达14.4 V的电源电压,三路用来监控高达6 V的电源电压,四路用来监控0.573 V至1.375 V的电源电压或者复位、电源良好、故障等数字信号。8路可编程输出可以在时序控制引擎的控制下分别使能各电源,其中六路输出可以向N沟道FET提供12 V栅极驱动。时序控制引擎提供多达63种状态,可以根据输入状况对输出进行灵活的时序控制。非易失性EEPROM可以存储用户自定义的数据,或者在时序控制引擎的控制下,它可以自动记录电源故障或系统输入故障。为提高冗余性,该器件采用电压监控输入端四个电压中的最高电压供电。ADM1168采用3 V至14.4 V电源供电,功耗为4.2 mA。它采用32引脚LQFP封装,额定温度范围为–40°C至+85°C,千片订量报价为5.49美元/片。

同步降压控制器利用PWM实现快速瞬变响应,并利用谷值电流模式提高噪声灵敏度

adp1874/adp1875 ADP1874ADP1875均为电流模式同步降压型控制器,采用恒定导通时间、伪固定频率电流控制方案,具备出色的瞬态响应、最佳稳定性和限流保护特性;谷值电流控制模式能够在低占空比时提供最佳性能。这些器件设计用来驱动N沟道功率级,可以调节低至0.6 V的输出电压。ADP1875还提供一种省电模式(PSM),能够利用脉冲跳跃维持输出调节,同时提高轻负载时的系统效率。这些器件提供三种频率选项:300 kHz、600 kHz和1.0 MHz,此外还有PSM选项。低压偏置通过内置的5 V低压差调节器(LDO)提供。可编程软启动功能在启动期间能够限制输入电源的浪涌电流,在预充电输出状况下能够提供反向电流保护。ADP184/75采用2.95 V至20 V输入电压,静态功耗为1.1 mA,关断模式下为140 µA。额定温度范围为–40°C至+125°C,采用16引脚QSOP封装,千片订量报价为1.32美元/片。

2011年4月

快速启动、具有振动抑制特性的偏航角速度陀螺仪,测量范围为±20,000°/s

adxrs649 ADXRS649角速率传感器采用先进的差分四传感器设计,可抑制冲击和振动的影响,有利于在恶劣的环境中执行检测。输出电压与Z轴的角速率成比例,与外部基准电压成比率关系。带宽范围为0.01 Hz至2 kHz,利用一个外部电容设置。通过增加一个外部电阻,可将测量范围扩大至±50,000°/s。该器件耗电量低,启动时间超快;以10 sps的速率工作时,一对CR2032纽扣电池可以供它持续工作三个月。两路数字自测输入提供机电激励,以测试传感器和信号调理电路是否正常工作。该器件提供温度输出,用于补偿方案。ADXRS649采用4.75 V至5.25 V单电源供电,功耗为3.5 mA。额定温度范围为–40°C至+105°C,提供7 mm × 7 mm × 3 mm CBGA芯片级封装,千片订量报价为47.97美元/片。

工作温度高达210°C的低噪声仪表放大器

ad8229 AD8229超低噪声仪表放大器非常适合在宽温度范围内测量极小信号。在210°C时,其保证工作时间为1000小时。它采用介质隔离工艺来防止产生寄生漏电流,封装中的线焊能够避免发生金属间吸收现象,这些技术增强了它在高温下的长期稳定性。这款放大器提供业界领先水平的1 nV/rt-Hz输入噪声和最大100 µV的输入失调电压,擅长测量微小信号。其共模抑制(CMR)可从G=1时的80 dB提高到G=1000时的134 dB,从而在最需要的时候提供高抑制性能;高性能引脚排列可保证DC至5 kHz范围内的CMR性能。电流反馈架构实现宽带宽和快速建立时间:15 MHz和0.75 µs(G=1时);4 MHz和0.65 µs(G=10时);1.2 MHz和0.85 µs(G=100时);0.15 MHz和5 µs(G=1000时)。增益通过单个外部电阻设置,增益范围为1至1000。可以利用参考引脚使输出电压偏移。AD8229采用±4 V至±17 V电源供电,整个温度范围内最大功耗为12 mA。额定温度范围为–40°C至+210°C,提供8引脚SBDIP封装,千片订量报价为100.00美元/片。

单相多功能电能计量IC可测量零线电流

ade7953 ADE7953是一款高性能单相电能计量IC,可测量交流线路电压和电流,并能计算有功、无功和视在电能以及瞬时电压和电流有效值,在3000:1动态范围内的误差小于0.1%,在1000:1动态范围内的误差小于0.2%。使用三个通道来测量线路电压、相位电流和零线电流,各通道均包括可编程增益放大器和Σ-Δ ADC;零线电流测量支持窃电检测和零线电流计费。该器件支持电流变压器、低值分流电阻和罗氏线圈电流传感器。电表寄存器可以通过SPI、I2C和UART接口进行访问。一个中断引脚提供过流、过压、峰值和骤降检测功能。反向电源和过零指示通过专用引脚提供,电能检测器可防止电表爬电。两个可配置的低抖动脉冲输出提供电能和均方根计算。ADE7953采用3.0 V至3.6 V单电源供电,功耗为6.8 mA。额定温度范围为–40°C至+85°C,提供28引脚LFCSP封装,千片订量报价为2.15美元/片。

低功耗、零中频、2.4 GHz收发器IC支持IEEE 802.15.4

adf7241 ADF7241高集成度、低功耗、高性能收发器ADF7241工作在全球通用的2.4 GHz ISM频段。在数据包和数据流两种模式下,该器件均支持IEEE 802.15.4-2006 PHY要求,并提供250 kbps的固定数据速率和DSSS-OQPSK调制功能。它符合FCC CFR47 Part 15、ETSI EN 300 440、ETSI EN 300 328和ARIB STD T-66标准。发射路径使用低噪声小数N分频RF频率合成器进行直接闭环VCO调制,其带宽自动优化,以实现最佳的相位噪声、调制质量和频率合成器建立时间性能。该VCO能够自动校准,工作频率是基频的两倍,因而可减少杂散发射并避免PA牵引效应。发射机输出功率可以在−20 dBm至+4 dBm范围内进行编程,且自动PA斜坡能力可满足瞬时杂散性能要求。集成的偏置和控制电路可简化与外部PA的接口。ADF7241采用1.8 V至3.6 V单电源供电,发射模式下功耗为21.5 mA,接收模式下为19 mA,休眠模式下为1.7 μA。它采用32引脚LFCSP封装,额定温度范围为–40°C至+85°C,千片订量报价为1.98美元/片。

技术文章

Michael Manning, Ask The Applications Engineer--40 Switch and Multiplexer Design Considerations for Hostile Environments, Analog Dialogue, 5/2/2011

Baoxing Chen, Potentialtrennung fur Daten Impulse und Stromversorgung, Elektronik, 5/1/2011

Matthew Duff and Joseph Towey, Making Thermocouple Measurement , Electronic Specifier Design , 5/1/2011

Moshe Gerstenhaber and Michael O'Sullivan, High-Resolution Temperature Measurement, Analog Dialogue, 4/5/2011

Kevin Tompsett, Use a Boost Regulator Well Beyond its Rated Voltage, Elektronik Praxis, 4/1/2011

Hein Marais, RS-485/RS-422 Circuit Implementation Guide, Komponenty I Technoligii, 4/1/2011

Baoxing Chen, Use transformer isolators to improve the digital control of motor drives, Electronics Weekly, 4/1/2011

Aileen Ritchie, The Past, Present, and Future of Single Phase Metering in India, Electronics Maker, 4/1/2011

Bob Scannell, Improving Industrial Control with MEMS Inertial Sensors, Electronic Products, 3/15/2011

Colm Ronan, Options and Solutions for Partitioning Isolated Power in Isolated RS-485 Nodes, Internal, 3/1/2011

Pam Aparo, 如何应对高温、恶劣、不利的环境, ECN, 1/28/2011

Henri Sino, 滤除电磁干扰以降低精密模拟应用的误差, Analog Dialogue, 1/11/2011

Bob Scannell, 通过精确可靠的振动检测实现基于状态的预见性维护, Sensors, 1/1/2011

Petre Minciunescu, 智能电网计量及合适的架构, Electronic Products, 12/21/2011

Neil Zhao, Wenshuai Liao, and Henri Sino, 宽动态范围的高端电流检测:三种解决方案, Analog Dialogue, 12/13/2010

Reza Moghimi, 仪表放大器对电阻不匹配的敏感度较低, EDN, 12/2/2010

James Frame, Jeritt Kent and Ian Lawee, 智能电网通信的发展:持续改进智能电网, Microwave Journal, 12/1/2010

网络研讨会和教程

应对电机控制的嵌入式设计挑战 -- 本研讨会于3月16日首播,主要介绍新的设计方法和设计流程以及一个完整的开放式系统设计,以便实现各种利用低成本处理器来完成数学计算密集型应用任务的终端解决方案,这在几年前是无法做到的。

变电站自动化中的电流和电压监控 -- 在这个50分钟的研讨会中,ADI公司专家将探讨变电站自动化和电力线监控系统中的电流和电压监控的设计挑战。

过程控制I/O模块的系统级模拟架构 -- 了解I/O模块设计的架构、关键技术规格、数据转换要求和技术趋势。

1 ppm精度电压源设计 -- 探讨基于20位DAC实现真1 ppm精度和分辨率基准电压源的设计考虑因素。

运算放大器简介 -- 本研讨会旨在向模拟设计新手或不熟悉模拟设计或概念者介绍运算放大器的基本知识。

实用放大器噪声原理 -- 本研讨会重点向电路板设计人员介绍一些实用的噪声处理技巧,而不是教科书中常见的理论知识。

 

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