MT8870 Integrated DTMF Receiver – DIP-18

Description

The MT8870 is a monolithic DTMF (Dual Tone Multi-Frequency) receiver that integrates both the band split filter and digital decoder functions into a single 18-pin package. It is specifically designed to detect and decode standard DTMF signals used in telecommunications, remote control systems, and automated signaling equipment.

The device operates by receiving the composite input signal (the sum of two tones) and processing it through high- and low-group filters to separate the individual frequencies. It then uses digital counting techniques to verify the frequency and provide a 4-bit binary output corresponding to the digit or character represented by the DTMF tone pair.

Note: Product images are for illustrative purposes only. Please refer to the official datasheet in the attachment section for detailed logic timing, input voltage requirements, and typical application circuit schematics.

Features

• Integrated Decoding: Combines band-split filtering and digital decoding in one IC.
• High Accuracy: Excellent performance in detecting all 16 standard DTMF tone pairs.
• Digital Output: Provides a 4-bit parallel interface to easily connect with microcontrollers or logic circuits.
• Adjustable Guard Time: Allows for configurable response times to prevent false triggering from noise.
• Standard Interface: Compatible with most CMOS and TTL logic levels.
• Package: DIP-18 through-hole package, ideal for breadboarding and rapid prototyping.

Benefits

• Simplicity: Greatly reduces the complexity of phone-line or audio-channel signaling projects.
• Reliability: Robust filtering ensures that only valid DTMF pairs are decoded, minimizing errors in noisy environments.
• Universal: Works with any audio source that produces standard DTMF signals (phones, radio transceivers, etc.).

Applications

• DTMF-based Remote Control Systems
• Telecommunications Equipment (PBX, Caller ID)
• Interactive Voice Response (IVR) systems
• Home Automation via telephone line
• Keypad data entry decoding

Package Includes

• 1 x MT8870 DTMF Decoder IC (DIP-18)

Specifications