Product Description

The CAMD CM8870/70C provides full DTMF receiver capability by integrating both the bandsplit filter and digital decoder functions into a single 18-pin DIP, SOIC, or 20-pin PLCC package. The CM8870/70C is manufactured using state-of-the-art CMOS process technology for low power consumption (35mW, max.) and precise data handling. The filter section uses a switched capacitor technique for both high and low group filters and dial tone rejection. The CM8870/70C decoder uses digital counting techniques for the detection and decoding of all 16 DTMF tone pairs into a 4-bit code. This DTMF receiver minimizes external component count by providing an on-chip differential input amplifier, clock generator, and a latched three-state interface bus. The on-chip clock generator requires only a low cost TV crystal or ceramic resonator as an external component.

Features

• Full DTMF receiver

• Less than 35mW power consumption

• Industrial temperature range

• Uses quartz crystal or ceramic resonators

• Adjustable acquisition and release times

• 18-pin DIP, 18-pin DIP EIAJ, 18-pin SOIC, 20-pin PLCC

• CM8870C

   — Power down mode

   — Inhibit mode

   — Buffered OSC3 output (PLCC package only)

• CM8870C is fully compatible with CM8870 for 18-pin devices by grounding pins 5 and 6

Applications

• PABX

• Central office

• Mobile radio

• Remote control

• Remote data entry

• Call limiting

• Telephone answering systems

• Paging systems