TEA1114AT/C2 View Datasheet(PDF) - Philips Electronics

Part Name

Description

Manufacturer

TEA1114AT/C2

Low voltage telephone transmission circuit with dialler interface and regulated strong supply

Philips Electronics 

Philips Semiconductors

Low voltage telephone transmission circuit with

dialler interface and regulated strong supply

Product specification

TEA1114A

handbook, full pagewidth Rline

Iline

ILN

LN

REXCH

ISUP

VEXCH

TEA1114A

RCC

ICC

VCC

SENSE

SWITCH

VDD regulator

VEE

VDD

IDD

CVCC

100 µF

peripherals

CVDD

220 µF

MGK807

Fig.6 VDD regulator configuration.

Set impedance

In the audio frequency range, the dynamic impedance is

mainly determined by the RCC resistor. The equivalent

impedance of the circuit is illustrated in Fig.7.

LN

handbook, halfpage

LEQ

RP

RCC

619 Ω

Vref

SLPE

VEE

RSLPE

20 Ω

REG

CREG

4.7 µF

VCC

CVCC

100 µF

MBE788

LEQ = CREG × RSLPE × RP.

RP = internal resistance.

RP = 17.5 kΩ.

Fig.7 Equivalent impedance between LN and VEE.

Transmit stage (pins MIC+, MIC− and DTMF)

MICROPHONE AMPLIFIER (PINS MIC+ AND MIC−)

The TEA1114A has symmetrical microphone inputs.

The input impedance between pins MIC+ and MIC− is

64 kΩ (2 × 32 kΩ). The voltage gain from pins MIC+/MIC−

to pin LN is set at 44.2 dB (typically).

Automatic gain control is provided on this amplifier for line

loss compensation.

DTMF AMPLIFIER (PIN DTMF)

When the DTMF amplifier is enabled, dialling tones may

be sent on line. These tones are also sent to the receive

output RX at a low level (confidence tone).

The TEA1114A has an asymmetrical DTMF input.

The input impedance between DTMF and VEE is 20 kΩ.

The voltage gain from pin DTMF to pin LN is set at 26 dB.

Automatic gain control has no effect on the DTMF

amplifier.

2000 Mar 21

8

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