GENERAL DESCRIPTION

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 integrateall 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 maximum supply current consumption is 115µA, making the AD5700/AD5700-1 an optimal choicefor lowpower 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.

FEATURES

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 (AD5700-1only)

Buffered HART output—extra drive capability

8 kV HBM ESD rating

1.71 V to 5.5 V power supply

1.71 V to 5.5 V interface

−40°C to +125°C operation

4 mm × 4 mm LFCSP package

HART physical layer compliant

UART interface

APPLICATIONS

Field transmitters

HART multiplexers

PLC and DCS analog I/O modules

HART network connectivity