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[原创]ADI AD4684 1 MSPS四路16位双同时取样SAR ADC解决方案

ADI公司的AD4684是 1 MSPS/500 kSPS四路16位双同时取样逐次逼近寄存器型(SAR)模数转换器(ADC),工作电压从3.0V到3.6V, AD4684吞吐量速率高达1MSPS, AD4685吞吐量速率高达500KSPS.模拟输入类型是单端和取样,转换在CS下降边沿. AD4684/AD4685具有片上定序器,集成了片上过取样区块,以改善动态范围,在低带宽时降低噪音.器件还包括缓冲内部2.5V基准电压.此外也可用高达3.3V的外接基准电压.转换过程和数据收集采用标准控制输入,允许接口到微处理器或数字信号处理器(DSP). AD4684/AD4685采用16引脚3mmx3mm LFCSP封装,工作温度从−40°C 到+125°C.主要用在马达控制位置反馈,马达控制电流检测,声纳,电源质量,数据采集系统,掺铒光纤放大器(EDFA)应用,相为和正交解调.本文介绍了AD4684产品亮点和主要特性,功能框图和典型应用电路图,以及评估板EVAL-AD7386FMCZ主要特性,电路图,材料清单和评估板EVAL-AD7386FMCZ和EVAL-SDP-CH1Z建立图.

The AD4684/AD4685 are 16-bit, dual, simultaneous sampling, high speed, successive approximation register (SAR), analog-to-digital converters (ADCs) that operate from a 3.0 V to 3.6 V power supply and feature throughput rates of up to 1 MSPS for the AD4684 and

500 kSPS for the AD4685. The analog input types are single-ended and are sampled and converted on the falling edge of CS.

The AD4684/AD4685 have an on-chip sequencer and integrated on-chip oversampling block to improve dynamic range and reduce noise at lower bandwidths. A buffered internal 2.5 V reference is included. Alternatively, an external reference up to 3.3 V can be used. The conversion process and data acquisition use standard control inputs, allowing interfacing to microprocessors or digital signal processors (DSPs). The AD4684/AD4685 is compatible with 1.8 V, 2.5 V, and 3.3 V interfaces by using the separate logic supply.

The AD4684/AD4685 are available in a 16-lead, 3 mm × 3 mm lead frame chip scale package (LFCSP) with operation specified from −40°C to +125°C.

AD4684产品亮点:

1. 4-channel, dual simultaneous sampling ADC.

2. Pin-compatible product family.

3. High throughput rate: 1 MSPS (AD4684) and 500 kSPS (AD4685).

4. Space-saving, 16-lead, 3 mm × 3 mm LFCSP.

5. Integrated oversampling block to increase dynamic range and SNR and to reduce SCLK speed requirements.

6. Single-ended analog inputs.

7. Small sampling capacitor reduces amplifier drive burden

AD4684主要特性:

► 16-bit dual simultaneous sampling SAR ADC

► Single-ended analog inputs

► 4-channel with 2:1 multiplexers

► Channel sequencer mode

► Throughput rate

► 1 MSPS (AD4684)

► 500 kSPS (AD4685)

► SNR (typical)

► 87.5 dB with VREF = 3.3 V external

► 93 dB with OSR_MODE = 1, OSR = 8, RES = 1, VREF = 2.5 V internal

► On-chip oversampling functions

► INL ±1.5 LSB (typical)

► Resolution boost function

► 2.5 V internal reference at 10 ppm/°C (maximum)

► Alert function

► −40°C to +125°C temperature range

► 16-lead, 3 mm × 3 mm LFCSP

AD4684应用:

► Motor control position feedback

► Motor control current sense

► Sonars

► Power quality

► Data acquisition systems

► Erbium doped fiber amplifier (EDFA) applications

► Inphase and quadrature demodulation

图1. AD4684功能框图

图2. AD4684典型应用电路图(VCM共模电压)

评估板EVAL-AD7386FMCZ

The EVAL-AD7386FMCZ is a full featured evaluation board designed to evaluate all the features of the AD7386 analog-to-digital converter (ADC). The evaluation board can be controlled by the EVAL-SDP-CH1Z via the 160-way system demonstration platform connector, P7. The EVAL-SDP-CH1Z board controls the evaluation board through the USB port of the PC using the Analysis Control Evaluation (ACE) software, which is available for download from the ACE software page.

The EVAL-AD7386FMCZ can evaluate the AD7387 and AD7388 by using the AD738x ACE plugin found on the EVAL-AD7386FMCZ product page. The only difference is the number of SCLKs that clock out the conversion results, which is dependent on the resolution for each generic.

Complete specifications for the AD7386/AD7387/AD7388 are provided in the AD7386/AD7387/AD7388 data sheet. Consult these specifications in conjunction with this user guide when using the evaluation board. Full details on the EVAL-SDP-CH1Z are available on the SDP-H1 product page. The comprehensive ACE user guide is available on the ACE software page.

评估板EVAL-AD7386FMCZ主要特性:

Full featured evaluation board multichannel, simultaneous sampling ADC

On-board reference, reference buffer, and ADC driver

On-board power supplies

Board-compatible high speed system demonstration platform (EVAL-SDP-CH1Z (SDP-H1)) controller

PC software for control and data analysis