原标题：ADI AD7091R-2多路12位超低功耗ADC评估方案

　　ADI公司的AD7091R-2/AD7091R- 4/AD7091R-8系列是多路12位超低功耗逐次逼近模数转换器(ADC),工作电压2.7V-5.25V,取样速率1MSPS,具有灵活的功率/吞吐量速率管理,超低功耗:正常模式1MSPS时为1.4mW,降功耗模式在VDD=5.25V时为550nA,VDD=3V时为435nA,主要用在电池工作系统,移动通信,医疗设备,数据采集系统,仪器仪表,个人数据助理,光学传感器和诊断/监视功能.本文介绍了AD7091R-2/4/8系列主要特性,框图,典型连接电路,以及评估板EVAL-AD7091R-2SDZ/4SDZ/8SDZ主要特性,框图,电路图,评估板PCB元件布局图和走线图.

　　The AD7091R-2/AD7091R-4/AD7091R-8 family is a multichannel 12-bit, ultralow power, successive approximation analog-todigital converter (ADC) that is available in two, four, or eight analog input channel options. The AD7091R-2/AD7091R-4/ AD7091R-8 operate from a single 2.7 V to 5.25 V power supply and are capable of achieving a sampling rate of 1 MSPS.

　　The AD7091R-2/AD7091R-4/AD7091R-8 family offers up to eight single-ended analog input channels with a channel sequencer that allows a preprogrammed selection of channels to be converted sequentially. The AD7091R-2/AD7091R-4/ AD7091R-8 also feature an on-chip conversion clock, an on-chip accurate 2.5 V reference, and a high speed serial interface.

　　The AD7091R-2/AD7091R-4/AD7091R-8 have a serial port interface (SPI) that allows data to be read after the conversion while achieving a 1 MSPS throughput rate. The conversion process and data acquisition are controlled using the CONVST pin.

　　The AD7091R-2/AD7091R-4/AD7091R-8 use advanced design techniques to achieve ultralow power dissipation at high throughput rates. They also feature flexible power management options. An on-chip configuration register allows the user to set up different operating conditions. These include power management, alert functionality, busy indication, channel sequencing, and general-purpose output pins. The MUXOUT and ADCIN pins allow signal conditioning of the multiplexer output prior to acquisition by the ADC.

　　AD7091R-2/4/8系列主要特性:

　　Ultralow system power

　　Flexible power/throughput rate management

　　Normal mode

　　1.4 mW at 1 MSPS

　　Power-down mode

　　550 nA typical at VDD = 5.25 V

　　435 nA typical at VDD = 3 V

　　Programmable ALERT interrupt pin (4-/8-channel models)

　　High performance

　　1 MSPS throughput with no latency/pipeline delay

　　SNR: 70 dB typical at 10 kHz input frequency

　　THD: −80 dB typical at 10 kHz input frequency

　　INL: ±0.7 LSB typical, ±1.0 LSB maximum

　　Small system footprint

　　On-chip accurate 2.5 V reference, 5 ppm/°C typical drift

　　MUXOUT/ADCIN to allow single buffer amplifier

　　Daisy-chain mode

　　16-lead, 20-lead, and 24-lead 4 mm × 4 mm LFCSP packages

　　16-lead, 20-lead, and 24-lead TSSOP packages

　　Easy to use

　　SPI/QSPI™/MICROWIRE™/DSP compatible digital interface

　　Integrated programmable channel sequencer

　　BUSY indication available (4-/8-channel models)

　　Built in features for control and monitoring applications

　　GPOx pins available (4-/8-channel models)

　　Wide operating range

　　Temperature range: −40℃ to +125℃

　　Specified for VDD of 2.7 V to 5.25 V

　　AD7091R-2/4/8系列应用:

　　Battery-powered systems

　　Personal digital assistants

　　Medical instruments

　　Mobile communications

　　Instrumentation and control systems

　　Data acquisition systems

　　Optical sensors

　　Diagnostic/monitoring functions

　　图1. AD7091R-2/4/8系列框图

　　图2. AD7091R-4/8带缓冲器的典型连接图

　　图3. AD7091R-4/8不带缓冲器的典型连接图

　　评估板EVAL-AD7091R-2SDZ/4SDZ/8SDZ

　　The EVAL-AD7091R-2SDZ, EVAL-AD7091R-4SDZ, and EVAL-AD7091R-8SDZ are full featured evaluation boards designed to allow the user to easily evaluate all features of the AD7091R-2/ AD7091R-4/ AD7091R-8 family of analog-to-digital converters (ADCs). The evaluation board can be controlled via the SDP connector (J13). The SDP board ( EVAL-SDP-CB1Z) allows the evaluation board to be controlled through the USB port of a PC using the evaluation board software available for download from the product page.On-board components include: the AD8031 high speed precision rail-to-rail op amp, the AD8032 high speed precision rail-to-rail dual op amp, the ADP3303 high accuracy 200 mA low dropout linear regulator, and the REF193 3.0 volt precision micropower, low dropout, low voltage reference.

　　评估板EVAL-AD7091R-2SDZ/4SDZ/8SDZ主要特性:

　　Full featured evaluation board for the AD7091R-2/AD7091R-4/AD7091R-8 family

　　On-board power supplies

　　Standalone capability

　　System demonstration platform (SDP) compatible ( EVAL-SDP-CB1Z)

　　PC software for control and data analysis (download from product page)

　　评估板EVAL-AD7091R-2SDZ/4SDZ/8SDZ包括:

　　Evaluation board

　　Screw/nut kit

　　Mains power supply adapter

　　图4. 评估板EVAL-AD7091R-2SDZ/4SDZ/8SDZ框图

　　图5.评估板(左)连接到SDP板(右)