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