TEA1111A View Datasheet(PDF) - Philips Electronics

Part Name

Description

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TEA1111A

Speech circuit with dialler interface,regulated supply and earpiece volume control

Philips Electronics 

Philips Semiconductors

Speech circuit with dialler interface, regulated

supply and earpiece volume control

Product specification

TEA1111A

PINNING

SYMBOL PIN

DESCRIPTION

LN

1 positive line terminal

SLPE

2 slope (DC resistance) adjustment

REG

3 line voltage regulator decoupling

IR

4 receive amplifier input

AGC

5 automatic gain control/

line loss compensation

DTMF

6 dual-tone multi-frequency input

VDD

MUTE

7 regulated supply for peripherals

8 mute input to select speech or

dialling mode (active LOW)

VCI

9 volume control input

VEE

10 negative line terminal

QR

11 earpiece amplifier output

GAR

12 earpiece amplifier gain adjustment

MIC+

13 non-inverting microphone amplifier

input

MIC−

LEDC

14 inverting microphone amplifier input

15 LED control output

VCC

16 supply voltage for internal circuit

handbook, halfpage

LN 1

SLPE 2

16 VCC

15 LEDC

REG 3

14 MIC−

IR 4

13 MIC+

TEA1111A

AGC 5

12 GAR

DTMF 6

11 QR

VDD 7

MUTE 8

10 VEE

9 VCI

FCA052

Fig.2 Pin configuration.

FUNCTIONAL DESCRIPTION

All data given in this chapter concerns typical values,

except when otherwise specified.

Supply (pins LN, SLPE, REG, VCC and VDD)

The supply for the TEA1111A and its peripherals is

obtained from the telephone line (see Fig.3).

THE LINE INTERFACE (PINS LN, SLPE AND REG)

The IC generates a stabilized reference voltage (Vref)

across pins LN and SLPE. Vref is temperature

compensated and can be adjusted by using an external

resistor (RVA). Vref equals 3.8 V and can be increased by

connecting RVA between pins REG and SLPE or

decreased by connecting RVA between pins REG and LN.

The voltage at pin REG is used by the internal regulator to

generate Vref and is decoupled by CREG, which is

connected to VEE. This capacitor, converted to an

equivalent inductance, (see Section “Set impedance”)

determines the set impedance conversion from its DC

value (RSLPE) to its AC value (RCC in the audio-frequency

range). The voltage at pin SLPE is proportional to the line

current.

The voltage at pin LN is:

VLN = Vref + RSLPE × ISLPE

ISLPE = Iline − ICC − IP − ISUP − ILEDC

where:

Iline = line current

ICC = current consumption of the IC

IP = supply current for external circuits

ISUP = current consumed between LN and VEE by the

VDD regulator

ILEDC = supply current for external LED circuitry.

The preferred value for RSLPE is 20 Ω. Changing RSLPE will

affect more than the DC characteristics; it also influences

the microphone and DTMF gains, the gain control

characteristics, the sidetone level and the maximum

output swing on the line.

The DC line current flowing into the set is determined by

the exchange supply voltage (VEXCH), the feeding bridge

resistance (REXCH), the DC resistance of the telephone

line (Rline) and the reference voltage (Vref). With line

currents below Ilow (9 mA), the internal reference voltage

(generating Vref) is automatically adjusted to a lower value.

1999 Nov 22

4

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