HT9170D-18SOPLF – HOLT

The HT9170D-18SOPLF is a CMOS integrated circuit manufactured by HOLT Integrated Circuits, designed for use in telecommunications signaling applications. Specifically, it functions as a DTMF (Dual-Tone Multi-Frequency) receiver, converting DTMF tones into a 4-bit binary code. This device operates from a single 5V power supply and features a power-down mode to minimize current consumption when inactive. The -18SOPLF designation indicates that the device is packaged in an 18-pin small outline package (SOP) suitable for surface mount assembly. It incorporates a band-split filter to separate high and low group tones, followed by zero-crossing detectors and digital decoding logic to accurately identify the received DTMF digit. The HT9170D-18SOPLF provides a stable and reliable solution for DTMF decoding in various telecom and control applications.