原标题：ADI AD4003 18位2 MSPS精密SAR ADC评估方案

　　ADI公司的AD4003是低噪声低功耗高速18位,2 MSPS精密逐次逼近型寄存器(SAR)模数转换器(ADC). 采用1.8 V电源供电,具有±VREF全差分输入范围,VREF范围为2.4 V至5.1 V, INL为±1.0 LSB(±3.8 ppm,最大值),保证18位无丢失码,主要用在自动测试设备

　　机器自动化,医疗设备,电池供电设备和精密数据采集系统.本文介绍了AD4003主要特性,功能框图和几种应用电路,以及AD4000/AD4003评估板主要特性,框图,电路图,材料清单和PCB设计图.

　　The AD4003 is a low noise, low power, high speed, 18-bit, 2 MSPSprecision successive approximation register (SAR) analog-to-digitalconverter (ADC). It incorporates ease of use features thatlower the signal chain power, reduce signal chain complexity, andenable higher channel density. The high-Z mode, coupled with along acquisition phase, eliminates the need for a dedicated highpower, high speed ADC driver, thus broadening the range of lowpower precision amplifiers that can drive this ADC directly, whilestill achieving optimum performance. The input span compressionfeature enables the ADC driver amplifier and the ADC to operateoff common supply rails without the need for a negative supplywhile preserving the full ADC code range. The low serialperipheral interface (SPI) clock rate requirement reduces thedigital input/output power consumption, broadens processoroptions, and simplifies the task of sending data across digitalisolation.

　　Operating from a 1.8 V supply, the AD4003 has a ±VREF fully differentialinput range with VREF ranging from 2.4 V to 5.1 V. The AD4003consumes only 16 mW at 2 MSPS with a minimum of 75 MHzSCK rate in turbo mode and achieves ±1.0 LSB (±3.8 ppm) INLmaximum, guaranteed no missing codes at 18 bits with 100.5 dBtypical SNR. The reference voltage is applied externally and canbe set independently of the supply voltage.

　　The SPI-compatible versatile serial interface features seven differentmodes including the ability, using the SDI input, to daisy-chainseveral ADCs on a single 3-wire bus and provides an optional busyindicator. The AD4003 is compatible with 1.8 V, 2.5 V, 3 V, and

　　5 V logic, using the separate VIO supply.

　　The AD4003 is available in a 10-lead MSOP or a 10-lead LFCSPwith operation specified from −40°C to +125°C. The device ispin compatible with the 16-bit, 2 MSPS AD4000.

　　AD4003主要特性:

　　Throughput: 2 MSPS maximum

　　INL: ±1.0 LSB (±3.8 ppm) maximum

　　Guaranteed 18-bit no missing codes

　　Low power

　　9.5 mW at 2 MSPS (VDD only)

　　80 μW at 10 kSPS, 16 mW at 2 MSPS (total)

　　SNR: 100.5 dB typical at 1 kHz, 99 dB typical at 100 kHz

　　THD: −123 dB typical at 1 kHz, −100 dB typical at 100 kHz

　　Ease of use features reduce system power and complexity

　　Input overvoltage clamp circuit

　　Reduced nonlinear input charge kickback

　　High-Z mode

　　Long acquisition phase

　　Input span compression

　　Fast conversion time allows low SPI clock rates

　　SPI-programmable modes, read/write capability, status word

　　Differential analog input range: ±VREF

　　0 V to VREF with VREF between 2.4 V to 5.1 V

　　Single 1.8 V supply operation with 1.71 V to 5.5 V logic interface

　　SAR architecture: no latency/pipeline delay

　　Guaranteed operation: −40°C to 125°C

　　Serial interface SPI-/QSPI-/MICROWIRE-/DSP-compatible

　　Ability to daisy-chain multiple ADCs and busy indicator

　　10-lead package: 3 mm × 3 mm LFCSP and 3 mm × 4.90 mmMSOP

　　AD4003应用:

　　Automatic test equipment

　　Machine automation

　　Medical equipment

　　Battery-powered equipment

　　Precision data acquisition systems

　　图1.AD4003功能框图

　　图2.AD4003多个电源的应用电路图

　　图3.AD4003单电源的应用电路图

　　图4.AD4003全差分放大器的应用电路图

　　图4.AD4003带全差分放大器的单端-差分转换应用电路图

　　AD4000/AD4003评估板

　　The AD4000/AD4003 family evaluation board covers the ease of use 16-/18-bit precision SAR ADCs. The AD4000/AD4003 are a low power 16-bit/18-bit precision SAR ADCs that offer very high performance with throughputs up to 2 MSPS. The evaluation board is designed to demonstrate the performance of the AD4000/ AD4003 family of ADCs and to provide an easy to understand interface for a variety of system applications. A full description of these products is available in their respective data sheets, which should be consulted when using this evaluation board.

　　The EVAL-AD4000FMZ/EVAL-AD4003FMCZ evaluation boards (see Figure 1) are ideal for use with Analog Devices, Inc., high speed system demonstration platform (EVAL-SDP-CH1Z). These evaluation boards interface to the SDP-H1 board via a 120-pin connector. SMA connectors, JP2 and JP3, are provided for the low noise analog signal source.

　　On-board components include a high precision buffered band gap 5.0 V reference (the ADR4550), a reference buffer (the ADA4807-1), a common-mode buffer (the ADA4807-1), a signal conditioning circuit with two op amps (the ADA4807-1), and a power supply to derive the necessary voltage levels to supply all voltage needs.

　　AD4000/AD4003评估板主要特性:

　　Fully featured evaluation board for 10-lead precision ADCs

　　Versatile analog signal conditioning circuitry

　　On-board reference, reference buffers, and ADC drivers

　　PC software for control and data analysis of time and frequency domain

　　System demonstration platform compatible (EVAL-SDP-CH1Z)

　　AD4000/AD4003评估板包括:

　　AD4000/AD4003 evaluation board

　　12 V wall adapter power supply

　　图5.AD400x评估板外形图

　　图6.AD400x评估板框图

　　AD400x评估板材料清单:

详情请见：

AD4003.pdf

UG-1042.pdf