DAC8740H

• HART-compliant physical layer modem
  • 1200-Hz, 2200-Hz HART FSK sinusoids
  • Register programmable amplitude of TX signals (DAC8741H only)
  • Integrated RX demodulator and band-pass filter with minimal external components
• FOUNDATION Fieldbus compatible H1 controller and medium attachment unit (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 at typical industrial operating temperature range (–40°C to +85°C)
• Integrated 1.5-V reference
• Flexible clocking options
  • Internal oscillator
  • External crystal oscillator
  • External CMOS clock
• Digital interface
  • DAC8740H: UART
  • DAC8741H: SPI
• Reliability: CRC bit error checking, watchdog timer (DAC8741H only)
• Wide operating temperature: –55°C to +125°C
• 4-mm × 4-mm QFN package

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The DAC8740H and DAC8741H (DAC874xH) are HART^®, FOUNDATION Fieldbus™, and PROFIBUS PA compatible low-power modems designed for industrial process control and industrial-automation applications.

In HART mode, the DAC874xH integrates all of 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 of the required circuitry to operate as half-duplex FOUNDATION Fieldbus compatible H1 controllers and 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 SPI interface. The SPI interface includes an SDO pin for daisy-chain support, various interrupts, and other extended features.