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.
• 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:
– Speech mode
– Ringer mode
– Trickle mode.
• Transmit stage with:
– Microphone amplifier with symmetrical high impedance inputs
– DTMF amplifier with confidence tone on receive output.
• Receive stage with:
– Receive amplifier with asymmetrical output
– 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.
• Line powered telephone sets with LCD module
• Cordless telephones
• Fax machines
• Answering machines.