ADI公司的AD5700/AD5700-1是HART FSK半雙工調制解調器單片解決方案，和HART物理層的需求兼容，集成了所有需要的濾波，信號調理，調制和解調，信號產生功能，外接元件很少，2V-5.5V電源，接口電平1.71V-5.5V，主要用在場發送器，HART復接器，HART網絡連接，PLC和DCS模擬I/O模塊。本文介紹了AD5700主要特性，方框圖，連接圖，回路供電的發送器框圖，HART智能發送器參考電路圖以及AD5700/AD5700-1 HART調制解調器評估板主要特性，電路圖，材料清單和PCB元件布局圖。

The AD5700/AD5700-1 are single-chip solutions, designed and specified to operate as a HART® FSK half-duplex modem, complying with the HART physical layer requirements. The AD5700/AD5700-1 integrate all of the necessary filtering, signal detection, modulating, demodulating and signal generation functions, thus requiring few external components. The 0.5% precision internal oscillator on the AD5700-1 greatly reduces the board space requirements, making it ideal for line-powered applications in both master and slave configurations. The maxi- mum supply current consumption is 115 μA, making the AD5700/ AD5700-1 an optimal choice for low power loop-powered applications. Transmit waveforms are phase continuous 1200 Hz and 2200 Hz sinusoids. The AD5700/AD5700-1 contain accurate carrier detect circuitry and use a standard UART interface.

AD5700主要特性：

HART-compliant fully integrated FSK modem

1200 Hz and 2200 Hz sinusoidal shift frequencies

115 μA maximum supply current in receive mode

Suitable for intrinsically safe applications

Integrated receive band-pass filter

Minimal external components required

Clocking optimized for various system configurations

Ultralow power crystal oscillator (60 μA maximum)

External CMOS clock source

Precision internal oscillator (AD5700-1 only)

Buffered HART output—extra drive capability

8 kV HBM ESD rating

2 V to 5.5 V power supply

1.71 V to 5.5 V interface

−40℃ to +125℃ operation

4 mm × 4 mm LFCSP package

HART physical layer compliant UART interface

AD5700應用：

Field transmitters

HART multiplexers

PLC and DCS analog I/O modules

HART network connectivity

圖1。AD5700方框圖

圖2。AD5700/01外接和內部濾波器選擇的連接圖

圖3。AD5700回路供電的發送器框圖

圖4。AD5700 HART智能發送器參考電路圖

AD5700/AD5700-1 HART調制解調器評估板

This user guide describes the evaluation board for the AD5700/ AD5700-1 Highway Addressable Remote Transducer (HART®) modem. This board can be used to evaluate either the AD5700 or the AD5700-1 part. Both can operate from a single 2 V to 5.5 V supply, with the AD5700-1 having the added feature of an integrated oscillator. Complete specifications for both products can be found in the AD5700/AD5700-1 data sheet available from Analog Devices, Inc., which should be consulted in conjunction with this user guide when using the evaluation board.

HART調制解調器評估板主要特性：

Convenient connections for power through screw

Terminal block

Use of on-chip RC oscillator or an external crystal

Various link options

EQUIPMENT NEEDED

Host controller with UART interface

圖5。HART調制解調器評估板外形圖

圖6。HART調制解調器評估板電路圖
HART調制解調器評估板材料清單（BOM）：


圖7。HART調制解調器評估板元件布局圖
詳情請見：
http://www.analog.com/static/imported-files/data_sheets/AD5700_5700-1.pdf
和
http://www.analog.com/static/imported-files/user_guides/UG-382.pdf