HT9170B/HT9170D -- DTMF Receiver

General Description

The HT9170B/D are Dual Tone Multi Frequency (DTMF) receivers integrated with digital decoder and bandsplit filter functions as well as power-down mode and inhibit mode operations. Such devices use digital counting techniques to detect and decode all the 16 DTMF tone pairs into a 4-bit code output.

Highly accurate switched capacitor filters are implemented to divide tone signals into low and high group signals. A built-in dial tone rejection circuit is provided to eliminate the need for pre-filtering.


  • Operating voltage: 2.5V~5.5V
  • Minimal external components
  • No external filter is required
  • Low standby current (on power down mode)
  • Excellent performance
  • Tristate data output for MCU interface
  • 3.58MHz crystal or ceramic resonator
  • 1633Hz can be inhibited by the INH pin
  • HT9170B: 18-pin DIP package
    HT9170D: 18-pin SOP package

Technical Document


Other Information