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