GENERAL DESCRIPTION
The TEA1114A is a bipolar integrated circuit that performs all speech and line interface functions required in fully electronic telephone sets. It performs electronic switching between speech and dialling. The IC operates at a line voltage down to 1.45 V DC (with reduced performance) to facilitate the use of telephone sets connected in parallel.
When the line current is high enough, a fixed amount of current is derived from the LN pin in order to create a strong supply point at pin VDD. The voltage at pin VDD is regulated to 3.3 V to supply peripherals such as dialler, LCD module and microcontroller.
FEATURES
⢠Low DC line voltage; operates down to 1.45 V
  (excluding voltage drop over external polarity guard)
⢠Line voltage regulator with adjustable DC voltage
⢠3.3 V regulated strong supply point for peripheral circuits compatible with:
  â Speech mode
  â Ringer mode
  â Trickle mode.
⢠Transmit stage with:
  â Microphone amplifier with symmetrical high impedance inputs
  â DTMF amplifier with confidence tone on receive output.
⢠Receive stage with:
  â Receive amplifier with asymmetrical output
  â Earpiece amplifier with adjustable gain (and gain boost facility) for all types of earpieces.
⢠MUTE input for pulse or DTMF dialling
⢠AGC line loss compensation for microphone and receive amplifiers.
APPLICATIONS
⢠Line powered telephone sets with LCD module
⢠Cordless telephones
⢠Fax machines
⢠Answering machines.
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