ADI公司的AD4002是低噪聲低功耗高速18 位取樣頻率2 MSPS 精密逐次逼近寄存器 （SAR） 模數(shù)轉(zhuǎn)換器 （ADC），集成了多種易用特性，可以減少信號(hào)鏈功率，降低信號(hào)鏈復(fù)雜性以及實(shí)現(xiàn)更高的通道密度.INL最大為±3.2 LSB，18位不丟碼，10kSPS時(shí)功耗70uW，2MSPS時(shí)為14mW，SNR在1kHz，VREF = 5 V時(shí)為95dB，THD在1 kHz，VREF = 5 V時(shí)為-125dB，主要用在自動(dòng)測(cè)試設(shè)備，機(jī)器自動(dòng)化，醫(yī)療器械，電池供電設(shè)備和精密數(shù)據(jù)采集系統(tǒng)。本文介紹了AD4002/AD4006/AD4010主要特性，功能框圖，ADC簡(jiǎn)化電路圖，典型應(yīng)用框圖，以及評(píng)估板EVAL-AD400xFMCZ主要特性，框圖，電路圖，材料清單和PCB設(shè)計(jì)圖。

The AD4002/AD4006/AD4010 are low noise， low power， high speed， 18-bit， precision successive approximation register （SAR） analog-to-digital converters （ADCs）。 The AD4002， AD4006， and AD4010 offer 2 MSPS， 1 MSPS， and 500 kSPS throughputs， respectively. They incorporate ease of use features that reduce signal chain power consumption， reduce signal chain complexity， and enable higher channel density. The high-Z mode， coupled with a long acquisition phase， eliminates the need for a dedicated high power， high speed ADC driver， thus broadening the range of low power precision amplifiers that can drive these ADCs directly while still achieving optimum performance. The input span com-pression feature enables the ADC driver amplifier and the ADC to operate off common supply rails without the need for a negative supply while preserving the full ADC code range. The low serial peripheral interface （SPI） clock rate requirement reduces the digital input/output power consumption， broadens processor options， and simplifies the task of sending data across digital isolation.

Operating from a 1.8 V supply， the AD4002/AD4006/AD4010 sample an analog input （IN+） from 0 V to VREF with respect to a ground sense （IN?） with VREF ranging from 2.4 V to 5.1 V. The AD4002 consumes only 14 mW at 2 MSPS with a minimum SCK rate of 75 MHz in turbo mode; the AD4006 consumes only 7 mW at 1 MSPS; and the AD4010 consumes only 3.5 mW at 500 kSPS. The AD4002/AD4006/AD4010 all achieve ±3.2 LSB integral nonlinearity error （INL） maximum， no missing codes at 18 bits， and 95 dB signal-to-noise ratio （SNR） for an input frequency （fIN） of 1 kHz. The reference voltage is applied externally and can be set independently of the supply voltage.

The SPI-compatible versatile serial interface features seven different modes including the ability， using the SDI input， to daisy-chain several ADCs on a single 3-wire bus， and provides an optional busy indicator. The AD4002/AD4006/AD4010 are compatible with 1.8 V， 2.5 V， 3 V， and 5 V logic， using the separate VIO supply.

The AD4002/AD4006 are available in a 10-lead MSOP and 10-lead LFCSP， and the AD4010 is available in a 10-lead LFCSP， with operation specified from ?40℃ to +125℃。 The devices are pin compatible with the 18-bit， 2 MSPS AD4003 （see Table 8）。

AD4002/AD4006/AD4010主要特性：

Throughput： 2 MSPS/1 MSPS/500 kSPS options

INL： ±3.2 LSB maximum

Guaranteed 18-bit， no missing codes

Low power： 70 μW at 10 kSPS， 14 mW at 2 MSPS （total）

9.75 mW at 2 MSPS， 4.9 mW at 1 MSPS， 2.5 mW at 500 kSPS （VDD only）

SNR： 95 dB typical at 1 kHz， VREF = 5 V; 95 dB typical at 100 kHz

THD： ?125 dB typical at 1 kHz， VREF = 5 V; ?108 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

Pseudo differential （single-ended） analog input range

0 V to VREF with VREF from 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， valid first conversion

First conversion accurate

Guaranteed operation： ?40℃ to +125℃

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

Ability to daisy-chain multiple ADCs and busy indicator

10-lead packages： 3 mm × 3 mm LFCSP， 3 mm × 4.90 mm MSOP

AD4002/AD4006/AD4010應(yīng)用：

Automatic test equipment

Machine automation

Medical equipment

Battery-powered equipment

Precision data acquisition systems

圖1.AD4002/AD4006/AD4010功能框圖

圖2.ADC簡(jiǎn)化電路圖

圖3.AD4002/AD4006/AD4010多個(gè)電源典型應(yīng)用框圖

圖4.AD4002/AD4006/AD4010單電源典型應(yīng)用框圖

評(píng)估板EVAL-AD400xFMCZ

The AD4000/AD4001/AD4002/AD4003/AD4020 family evaluation board covers the ease of use， 16-/18-/20-bit， precision successive approximation register （SAR） analog-to-digital converters （ADCs）。 The AD4000/AD4001/AD4002/ AD4003/AD4020 are low power， 16-bit/18-bit/20-bit， precision SAR ADCs that offer very high performance with throughputs up to 2 MSPS （1.8 MSPS for the AD4020）。 The evaluation board is designed to demonstrate the performance of the AD4000/AD4001/AD4002/AD4003/AD4020 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 must be consulted when using this evaluation board.

The EVAL-AD4000FMCZ/EVAL-AD4001FMCZ/EVAL-AD4002FMCZ/EVAL-AD4003FMCZ/EVAL-AD4020FMCZ evaluation boards （see Figure 1） are ideal for use with the 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.

The EVAL-AD4000FMCZ， EVAL-AD4001FMCZ， EVAL-AD4002FMCZ， and EVAL-AD4003FMCZ are populated with the AD4000， AD4001， AD4002， and AD4003， respectively. However， these boards can be used to evaluate the performance of the AD4004， AD4005， AD4006， AD4007， AD4008， AD4010， and AD4011 by limiting the sample rate in the evaluation software to the maximum sample rate of the specific ADC. For example， the AD4000 on the EVAL-AD4000FMCZ can be used to evaluate the performance of the AD4004 if the sample rate is limited to 1 MSPS. See the data sheet of each product for its corresponding evaluation board.

圖5.評(píng)估板EVAL-AD400xFMCZ外形圖

圖6.評(píng)估板EVAL-AD400xFMCZ簡(jiǎn)化框圖

圖7.評(píng)估板EVAL-AD400xFMCZ電路圖(1):電源

圖8.評(píng)估板EVAL-AD400xFMCZ電路圖(2):基準(zhǔn)電壓,共模和基準(zhǔn)緩沖器

圖9.評(píng)估板EVAL-AD400xFMCZ電路圖(3):ADC驅(qū)動(dòng)器和ADC

圖10.評(píng)估板EVAL-AD400xFMCZ電路圖(4):SDP-H1連接器和膠合邏輯

評(píng)估板EVAL-AD400xFMCZ材料清單:

圖11.評(píng)估板EVAL-AD400xFMCZ PCB設(shè)計(jì)圖:頂層絲印

圖12.評(píng)估板EVAL-AD400xFMCZ PCB設(shè)計(jì)圖:層1

圖13.評(píng)估板EVAL-AD400xFMCZ PCB設(shè)計(jì)圖:層2

圖14.評(píng)估板EVAL-AD400xFMCZ PCB設(shè)計(jì)圖:層3

圖15.評(píng)估板EVAL-AD400xFMCZ PCB設(shè)計(jì)圖:層4