DAC874xH Low-Power Modems

DAC874xH Low-Power Modems

Texas Instruments' DAC8740H and DAC8742H are HART, FOUNDATION Fieldbus, and PROFIBUS PA-compatible low power modems for industrial process control and industrial automation applications.

In HART mode, the DAC874xH integrates all the required circuitry to operate as half-duplex HART physical layer modems, in either slave or master configurations with minimal external components for filtering. In FOUNDATION Fieldbus mode, the DAC874xH integrates all the required circuitry to operate as half-duplex FOUNDATION Fieldbus-compatible H1 controllers and medium attachment units (MAUs).

The HART, FOUNDATION Fieldbus, or PROFIBUS PA, data stream can be transferred from the microcontroller through either a UART interface or an integrated FIFO accessed by a serial peripheral interface (SPI). The SPI includes an SDO pin for daisy-chain support, various interrupts, and other extended features.

  • HART-compliant physical layer modem
    • 1200/2200 Hz HART FSK sinusoids
    • Register programmable amplitude of TX signals (DAC8742H only)
    • Integrated RX demodulator and band-pass filter with minimal external components
  • FOUNDATION Fieldbus compatible H1 controller and MAU
    • 31.25 kbit/s communication based on Manchester coded bus powered (MBP)
    • Integrated Manchester encoder and decoder
    • Compatible with PROFIBUS PA
  • Low quiescent current: 180 µA max. (typ.) industrial operating temperature range -40°C to +85°C
  • Flexible clocking options
    • Internal oscillator
    • External crystal oscillator
    • External CMOS clock
  • Digital interface
    • DAC8740H: UART
    • DAC8742H: UART and SPI
  • Reliability: CRC bit error checking, watchdog timer (DAC8742H only)
  • Wide operating temperature: -55°C to +125°C
  • 4 mm x 4 mm QFN and 5 mm x 5 mm TQFP packages
  • Integrated 1.5 V reference
  • Industrial process control and automation
  • PLC or DCS I/O modules
  • Field and sensor transmitters

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