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.

Features

• 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