Integrated DTMF Receiver With Enhance Sensitivity

The MT8870 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 tone-pairs 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
By Zarlink Semiconductor