HT9172D(LX)

The HT9172 is a complete DTMF receiver circuit featuring band-split filtering and digital decoding, with power-down and inhibit operating modes. The filter section employs switched-capacitor technology to separate the dial tone signal into high-group and low-group signals. Digital counting techniques are used in the decoder to detect all 16 DTMF tone pairs and encode them into a 4-bit output. The circuit incorporates a built-in dial tone rejection function, along with a differential input amplifier, clock oscillator, and three-state latched bus interface, minimizing the number of external components required.

Key features

• Operating voltage range: 2.5V~5.5V
• Minimal external components
• No external filter required
• Low standby current and low power consumption in power-down mode
• Superior performance
• Uses 3.58MHz crystal or clock
• MCU interface with tri-state output
• 1633Hz inhibit via INH
• Package: DIP18 / SOP18 / DIE