MT88L85

Features:

• External power down pin
• Low voltage operation (2.7V - 3.6V)
• 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


Application

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


Pinout

Specifications

	Parameter	Symbol	Min	Max	Units
1	Power supply voltage VDD-VSS	VDD		6	V
2	Voltage on any pin	VI	VSS-0.3	VDD+0.3	V
3	Current at any pin (Except VDD and VSS)			10	mA
4	Storage Temperature	TST	-65	+150	°C
5	Package power dissipation	PD		1000	mW

Description

The MT88L85 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 of MT88L85 is based upon the industry standard MT8870 DTMF receiver while the transmitter utilizes a swit-ched 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 of MT88L85 can be selected allowing a micro-processor to analyze call progress tones.

The MT88L85 utilizes an adaptive micro interface,which allows the device to be connected to a number of popular microcontrollers with minimal external logic. The MT88L85 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.