TEA1114AT View Datasheet(PDF) - Philips Electronics

Part Name

Description

Manufacturer

TEA1114AT

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

THE INTERNAL SUPPLY POINT (PIN VCC)

The internal circuitry of the TEA1114A is supplied from

pin VCC. This voltage supply is derived from the line

voltage by means of a resistor (RCC) and must be

decoupled by a capacitor CVCC. It may also be used to

supply some external circuits. The VCC voltage depends

on the current consumed by the IC and the peripheral

circuits as: VCC0 = VLN – RCC × ICC

VCC = VCC0 – RCC × (IP + Irec)

(see also Figs 4 and 5). Irec is the current consumed by the

output stage of the earpiece amplifier.

3

handbook, halfpage

IP

(mA)

1.9 mA

2

1.6 mA

1

Product specification

TEA1114A

MGL827

(2) (1)

handbook, halfpage RCC VCC

VCC0

Irec

EXTERNAL

CIRCUITS

IP

VEE

MGK806

Fig.4 VCC used as supply voltage for external

circuits.

0

0

1

2

3

4

VCC (V)

VCC ≥ 2.5 V; VLN = 4.35 V at Iline = 15 mA; RCC = 619 Ω;

RSLPE = 20 Ω.

Curve (1) is valid when the receiving amplifier is driven:

VQR(rms) = 150 mV; RL1 = 150 Ω.

Curve (2) is valid when the receiving amplifier is not driven.

Fig.5 Typical current IP available from VCC for

peripheral circuitry.

THE REGULATED SUPPLY POINT (PIN VDD)

The VDD regulator delivers a stabilized voltage for the

peripherals in transmission mode (nominal VLN) as well as

in ringer mode (VLN = 0 V). The regulator (see Fig.6)

consists of a sense input circuit, a current switch and a VDD

output stabilizer. The regulator operates as a current

source at the LN input in transmission mode; it takes a

constant current of 4.3 mA (at nominal conditions) from

pin LN. The current switch reduces the distortion on the

line at large signal swings. Output VDD follows the

DC voltage at pin LN (with typically 0.35 V difference) up

to VDD = 3.3 V. The input current of the regulator is

constant while the output (source) current is determined by

the consumption of the peripherals. The difference

between input and output current is shunted by the internal

VDD stabilizer.

In ringer mode, the stabilizer operates as a shunt stabilizer

to keep VDD at 3.3 V. In this mode, the input voltage

VLN = 0 V while the input current into pin VDD is delivered

by the ringing signal. VDD has to be decoupled by a

capacitor CVDD.

2000 Mar 21

7

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