Low voltage telephone transmission circuit with
dialler interface and regulated strong supply
• 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
– DTMF amplifier with confidence tone on receive
• 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
• Line powered telephone sets with LCD module
• Cordless telephones
• Fax machines
• Answering machines.
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.
plastic dual in-line package; 16 leads (300 mil)
plastic small outline package; 16 leads; body width 3.9 mm
bare die; on foil
2000 Mar 21