ADI公司的AD5700/AD5700-1是HART FSK半双工调制解调器单片解决方案，和HART物理层的需求兼容，集成了所有需要的滤波，信号调理，调制和解调，信号产生功能，外接元件很少，2V-5.5V电源，接口电平1.71V-5.5V，主要用在场发送器，HART复接器，HART网络连接，PLC和DCS模拟I/O模块。本文介绍了AD5700主要特性，方框图，连接图，回路供电的发送器框图，HART智能发送器参考电路图以及AD5700/AD5700-1 HART调制解调器评估板主要特性，电路图，材料清单和PCB元件布局图。

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应用：

Field transmitters

HART multiplexers

PLC and DCS analog I/O modules

HART network connectivity

图1。AD5700方框图

图2。AD5700/01外接和内部滤波器选择的连接图

图3。AD5700回路供电的发送器框图

图4。AD5700 HART智能发送器参考电路图

AD5700/AD5700-1 HART调制解调器评估板

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调制解调器评估板主要特性：

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

图5。HART调制解调器评估板外形图

图6。HART调制解调器评估板电路图
HART调制解调器评估板材料清单（BOM）：


图7。HART调制解调器评估板元件布局图
详情请见：
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