HT9170B DTMF Receiver/Decoder IC – 4-Bit Output – DIP-18 – Holtek

The Holtek HT9170B is a CMOS Dual-Tone Multi-Frequency (DTMF) receiver and decoder IC designed to reliably decode standard telephone tone pairs into a 4-bit binary output. Packaged in a durable 18-pin DIP (through-hole) format, it is ideal for telecom systems, tone-based control modules, remote access devices, home automation, and microcontroller-controlled signaling interfaces.

This IC decodes all 16 standard DTMF tone pairs and outputs the corresponding data through a tri-state 4-bit interface, allowing seamless integration with microcontrollers. It operates from 2.5V to 5.5V, making it suitable for both low-voltage and 5V systems.

The HT9170B requires an external 3.58 MHz crystal or ceramic resonator for precise tone decoding. It includes a built-in dial-tone rejection circuit, eliminating the need for external filtering. Additional features include low standby current, a power-down mode, and a Data Valid (DV) pin for reliable data acquisition.

Key Specifications:

• Manufacturer: Holtek

• Part Number: HT9170B

• Function: DTMF receiver and decoder

• Output: 4-bit binary (tri-state output for MCU interface)

• Decoding: 16 DTMF tone pairs

• Operating Voltage: 2.5V to 5.5V

• External Oscillator: 3.58 MHz crystal/resonator

• Features:
  – Dial-tone rejection circuit
  – Low standby current
  – Power-down control
  – Data Valid (DV) output

• Package: DIP-18 (through-hole)

Package Includes:
1 x HT9170B DTMF Receiver/Decoder IC

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