Description
The MT8885 is a monolithic DTMF transceiver with call progress filter. It is fabricated in CMOS technology offering low power consumption and high reliability.
The receiver section is based upon the industry standard MT8870 DTMF receiver while the transmitter utilizes a switched capacitor D/A converter for low distortion, high accuracy DTMF signalling. Internal counters provide a burst mode such that tone bursts can be transmitted with precise timing. A call progress filter can be selected allowing a microprocessor to analyze call progress tones.
The MT8885 utilizes an adaptive micro interface, which allows the device to be connected to a number of popular microcontrollers with minimal external logic. The MT8885 provides enhanced power down features. The transmitter and receiver may independently be powered down via register control. A full chip power down pin provides simple power and control capability.

Features
• External power down pin
• Central office quality DTMF transmitter/ receiver
• Low power consumption
• High speed adaptive micro interface
• Adjustable guard time
• Automatic tone burst mode
• Call progress tone detection to -30dBm
• DTMF transmitter/receiver power down via register control

Applications
• Credit card systems
• Paging systems
• Repeater systems/mobile radio
• Interconnect dialers
• Personal computers