The AD5700/AD5700-1 are single-chip solutions， designed and specified to operate as a HART? FSKhalf-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 fewexternal 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 theAD5700/ AD5700-1 an optimal choiceforlowpowerloop-powered applications. Transmit waveforms are phase continuous 1200 Hz and 2200 Hz sinusoids. The AD5700/AD5700-1 containaccurate carrier detect circuitry and use a standard UART interface