原标题：ADI AD7403高性能二阶Σ-Δ调制解决方案

　　ADI公司的AD7403是高性能二阶Delta-Sigma调制器,能把模拟输入信号转换成高速单比特数据流,外时钟频率5-20MHz,16位不丢失码,SNR 88dB,温度漂移1.6 μV/℃, 满刻度输入范围±320 mV,工作温度−40℃ 到 + 125℃,主要用在马达控制,电源和太阳能逆变器,数据采集系统,风能逆变器,并联电流监视器等.本文介绍了AD7403主要特性,框图, 评估板EVAL-AD7403FMCZ主要特性,框图,电路图,材料清单和PCB元件布局图.

　　The AD7403 is a high performance, second-order, Σ-Δ modulator that converts an analog input signal into a high speed, single-bit data stream, with on-chip digital isolation based on Analog Devices, Inc., iCoupler® technology. The AD7403 operates from a 5 V (VDD1) power supply and accepts a differential input signal of ±250 mV (±320 mV full-scale). The differential input is ideally suited to shunt voltage monitoring in high voltage applications where galvanic isolation is required.

　　The analog input is continuously sampled by a high performance analog modulator, and converted to a ones density digital output stream with a data rate of up to 20 MHz. The original information can be reconstructed with an appropriate digital filter to achieve 88 dB signal to noise ratio (SNR) at 78.1 kSPS. The serial input/output can use a 5 V or a 3 V supply (VDD2).

　　The serial interface is digitally isolated. High speed complementary metal oxide semiconductor (CMOS) technology, combined with monolithic transformer technology, means the on-chip isolation provides outstanding performance characteristics, superior to alternatives such as optocoupler devices. The AD7403 device is offered in a 16-lead, wide-body SOIC package and has an operating temperature range of −40℃ to +125℃.

　　AD7403主要特性:

　　5 MHz to 20 MHz external clock input rate

　　16 bits, no missing codes

　　Signal-to-noise ratio (SNR): 88 dB typical

　　Effective number of bits (ENOB): 14.2 bits typical

　　Typical offset drift vs. temperature: 1.6 μV/℃ typical

　　On-board digital isolator

　　On-board reference

　　Full-scale analog input range: ±320 mV

　　−40℃ to + 125℃ operating range

　　High common-mode transient immunity: >25 kV/μs

　　16-lead, wide-body SOIC, with increased creepage package

　　Slew rate limited output for low electromagnetic interference (EMI)

　　Safety and regulatory approvals (pending)

　　UL recognition

　　5000 V rms for 1 minute per UL 1577

　　CSA Component Acceptance Notice 5A

　　VDE Certificate of Conformity

　　DIN V VDE V 0884-10 (VDE V 0884-10):2006-12

　　VIORM = 1250 VPEAK

　　AD7403应用:

　　Shunt current monitoring

　　AC motor controls

　　Power and solar inverters

　　Wind turbine inverters

　　Data acquisition systems

　　Analog-to-digital and opto-isolator replacements

　　图1. AD7403框图

　　评估板EVAL-AD7403FMCZ

　　The EVAL-AD7403FMCZ is a full featured evaluation board designed to allow the user to easily evaluate all features of the AD7403 isolated analog-to-digital converter (ADC). The evaluation board can be controlled by the EVAL-SDP-CH1Z via FMCZ connector (J9). The SDP-H1 board (EVAL-SDP-CH1Z) allows the evaluation board to be controlled through a USB port of a PC using the evaluation board software available for download from the product page or from the included installer CD.

　　On-board components include the following:

　　ADuM6000: isolated iCoupler® 5kV, DC / DC converter

　　ADP2441: 36 V, 1A, synchronous, step down DC-DC regulator

　　ADP7104ARDZ-5.0: 5 V low noise LDO

　　评估板EVAL-AD7403FMCZ主要特性:

　　Full featured evaluation board for the AD7403

　　On-board power supplies

　　Standalone capability

　　System demonstration platform (SDP-H1) compatible (EVAL-SDP-CH1Z)

　　PC software for control and data analysis (CD with software included in evaluation kit)

　　评估板EVAL-AD7403FMCZ包括:

　　Evaluation board

　　CD containing evaluation board software installation

　　Additional Equipment Required

　　EVAL-SDP-CH1Z (must be ordered separately) includes a USB cable and 12v wall wart.

　　Signal source

　　PC running Windows XP SP3, Windows Vista, or Windows 7 with USB 2.0 port

　　图2.评估板EVAL-AD7403FMCZ(左)和EVAL-SDP-CH1Z(右)的建立图

　　图3.评估板EVAL-AD7403FMCZ框图

　　图4.评估板EVAL-AD7403FMCZ电路图(1)

　　图5.评估板EVAL-AD7403FMCZ电路图(2)