HT9170

The HT9170 series are Dual Tone Multi Frequency (DTMF) receivers integrated with digital decoder and bandsplit filter functions. The HT9170B and HT9170D types supply power-down mode and inhibit mode operations. All types of the series 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 employed by HT9170 to divide tone (DTMF) signals into low and high group signals. A built-in dial tone rejection circuit is provided to eliminate the need for pre-filtering.