MT8870DE Very Large Scale Integrated Circuits Ics Complete DTMF Receiver

MT8870DE Very Large Scale Integrated Circuits Ics Complete DTMF Receiver

Features

• Complete DTMF Receiver

• Low power consumption

• Internal gain setting amplifier

• Adjustable guard time

• Central office quality

• Power-down mode

• Inhibit mode

• Backward compatible with MT8870C/MT8870C-1

Description

The MT8870D/MT8870D-1 is a complete DTMF receiver integrating both the bandsplit filter and digital decoder functions. The filter section uses switched capacitor techniques for high and low group filters; the decoder uses digital counting techniques to detect and decode all 16 DTMF tonepairs into a 4-bit code. External component count is minimized by on chip provision of a differential input amplifier, clock oscillator and latched three-state bus interface.

Applications

• Receiver system for British Telecom (BT) or CEPT Spec (MT8870D-1)

• Paging systems

• Repeater systems/mobile radio

• Credit card systems

• Remote control

• Personal computers

• Telephone answering machine

Figure 1 - Functional Block Diagram

Figure 2 - Pin Connections

Functional Description​

The MT8870D/MT8870D-1 monolithic DTMF receiver

offers small size, low power consumption and high

performance. Its architecture consists of a bandsplit

filter section, which separates the high and low group

tones, followed by a digital counting section which

verifies the frequency and duration of the received

tones before passing the corresponding code to the output bus.

electronics ic chip

integrated circuit ic

MT8870DE Very Large Scale Integrated Circuits Ics Complete DTMF Receiver Images