TDA1064A SMD telephone transmission circuit with dialler interface

Low voltage versatile telephone transmission circuit with dialler interface

and transmit level dynamic limiting

 

The TEA1064A is a bipolar integrated circuit that performs

all the speech and line interface functions required in fully

electronic telephone sets. It performs electronic switching

between dialling and speech and has a powerful DC

supply for peripheral circuits. The IC operates at line

voltages down to 1.8 V DC (with reduced performance) to

facilitate the use of more telephone sets connected in

parallel. The transmit signal on the line is dynamically

limited (speech-controlled) to prevent distortion at high

 

transmit levels of both the sending signal and the sidetone.

 

FEATURES

• Low DC line voltage; operates down to 1.8 V (excluding polarity guard)

• Voltage regulator with low voltage drop and adjustable static resistance

• DC line voltage adjustment facility

• Provides a supply for external circuits in two options:

unregulated supply, regulated line voltage;

stabilized supply, line voltage varies with supply current

• Dynamic limiting (speech-controlled) in transmit direction prevents distortion of line signal and sidetone

• Symmetrical high-impedance inputs (64 kΩ) for dynamic, magnetic or piezo-electric microphones

• Asymmetrical high-impedance input (32 kΩ) for electret microphones

• DTMF signal input

• Confidence tone in the earpiece during DTMF dialling

• Mute input for disabling speech during pulse or DTMF dialling

• Power-down input for improved performance during pulse dial or register recall (flash)

• Receiving amplifier for magnetic, dynamic or piezo-electric earpieces

• Large amplification setting ranges on microphone and earpiece amplifiers

• Line loss compensation (line current dependent) for microphone and earpiece amplifiers (not used for DTMF amplifier)

• Gain control curve adaptable to exchange supply

• Automatic disabling of the DTMF amplifier in extremely-low voltage conditions

• Microphone MUTE function available with switch