HT9170D DTMF Receiver/Decoder IC – 4-Bit Output – SOIC-18 – Holtek

The Holtek HT9170D is a CMOS Dual-Tone Multi-Frequency (DTMF) receiver and decoder IC designed to decode standard telephone tone signals and output the result as a clean, easy-to-interface 4-bit binary code. This version comes in an SOIC-18 (SOP-18) surface-mount package, ideal for compact and modern PCB layouts.

Supporting both 2-of-8 and 1-of-16 output formats, the HT9170D offers flexibility for telecom systems, tone-based remote control, automation modules, access control systems, and MCU-driven communication interfaces. An external 3.579545 MHz crystal or ceramic resonator ensures precise tone detection and stable filtering performance.

Operating over a wide 3.5V to 6V range, the IC delivers reliable decoding even under varying signal conditions. Key features include a Data Valid (DV) output pin, power-down mode, and excellent tolerance to tone distortion and amplitude variations.

Packaged in an SOIC-18 surface-mount format, the HT9170D is well suited for high-density PCB designs and commercial telecom hardware.

Key Specifications:

• Manufacturer: Holtek

• Part Number: HT9170D

• Function: DTMF receiver/decoder

• Output Format: 4-bit (selectable 2-of-8 or 1-of-16)

• Operating Voltage: 3.5V to 6V

• External Oscillator: 3.579545 MHz crystal/resonator

• Features:
  – Data Valid (DV) indication pin
  – Power-down control
  – High-accuracy tone decoding
  – Tolerant to signal distortion

• Package: SOIC-18 / SOP-18 (surface mount)

Package Includes:
1 x HT9170D DTMF Receiver/Decoder IC (SOIC-18)

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