Philips tea1114a DATASHEETS

INTEGRATED CIRCUITS

DATA SH EET

TEA1114A

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

Product speciﬁcation Supersedes data of 1999 Sep 14 File under Integrated Circuits, IC03

2000 Mar 21

Philips Semiconductors Product speciﬁcation

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

FEATURES

• 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

• AGClinelosscompensationformicrophoneandreceive

amplifiers.

APPLICATIONS

• Line powered telephone sets with LCD module

• Cordless telephones

• Fax machines

• Answering machines.

GENERAL DESCRIPTION

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.

TEA1114A

ORDERING INFORMATION

TYPE

NUMBER

TEA1114A DIP16 plastic dual in-line package; 16 leads (300 mil) SOT38-4 TEA1114AT SO16 plastic small outline package; 16 leads; body width 3.9 mm SOT109-1 TEA1114AUH − bare die; on foil −

NAME DESCRIPTION VERSION

PACKAGE

2000 Mar 21 2

Philips Semiconductors Product speciﬁcation

Low voltage telephone transmission circuit with

TEA1114A

dialler interface and regulated strong supply

QUICK REFERENCE DATA

= 15 mA; VEE=0V;R

line

circuits given in Figs 15, 16 and 17; T speciﬁed.

SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT

V I V

line

line current operating range normal operation 11 − 140 mA

DC line voltage 4.05 4.35 4.65 V internal current consumption VCC= 3.6 V − 1.25 1.5 mA supply voltage for internal circuitry

(unregulated)

regulated supply voltage for peripherals

speech mode I ringer mode I

v(TX)

available supply current for peripherals −−−3mA typical voltage gain for microphone

ampliﬁer

∆G ∆G

v(RX)

v(QR) v(trx)

typical voltage gain for receiving ampliﬁer VIR= 4 mV (RMS) 32.4 33.4 34.4 dB gain setting range for earpiece ampliﬁer RE1= 100 kΩ−14 − +12 dB gain control range for microphone and

receive ampliﬁers with respect to I

=15mA

line

∆G

v(trx)(m)

gain reduction for microphone and receive ampliﬁers

=20Ω;AGC pin connected to VEE;Z

SLPE

=25°C for TEA1114A(T); Tj=25°C for TEA1114AUH; unless otherwise

amb

= 600 Ω; f = 1 kHz; measured according to test

line

with reduced performance 1 − 11 mA

IP=0mA − 3.6 − V

= −3 mA 3.0 3.3 3.6 V

= 75 mA 3.0 3.3 3.6 V

= 4 mV (RMS) 43.2 44.2 45.2 dB

MIC

=85mA − 6.0 − dB

line

MUTE = LOW − 80 − dB

2000 Mar 21 3

Philips Semiconductors Product speciﬁcation

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

BLOCK DIAGRAM

handbook, full pagewidth

48IR

MUTE

6DTMF

ATTENUATOR

0.5V

TEA1114A

1211RX

GAR

9QR

CURRENT AND

VOLTAGE

REFERENCE

MIC+ MIC−

AGC

REGULATOR

TEA1114A

AGC

CIRCUIT

LOW VOLTAGE

CIRCUIT

SLPE

1LN

3 REG

MGK804

Fig.1 Block diagram.

2000 Mar 21 4

Philips Semiconductors Product speciﬁcation

Low voltage telephone transmission circuit with

TEA1114A

dialler interface and regulated strong supply

PINNING

SYMBOL

LN 1 1, 19 positive line terminal SLPE 2 2 slope (DC resistance) adjustment REG 3 3 line voltage regulator decoupling IR 4 4 receiving ampliﬁer input AGC 5 5 automatic gain control/ line loss compensation DTMF 6 6 dual-tone multi-frequency input V

MUTE 8 8 mute input to select speech or dialling mode (active LOW) QR 9 9 earpiece ampliﬁer output n.c. − 10 not connected V

n.c. − 12 not connected GAR 11 13 earpiece ampliﬁer gain adjustment RX 12 14 receive ampliﬁer output MIC+ 13 15 non-inverting microphone ampliﬁer input MIC− 14 16 inverting microphone ampliﬁer input n.c. 15 − not connected V

n.c. − 18 not connected

PIN PAD

DESCRIPTION

TEA1114A(T) TEA1114AUH

7 7 regulated supply for peripherals

10 11 negative line terminal

16 17 supply voltage for internal circuit

handbook, halfpage

SLPE

REG

AGC

DTMF

MUTE

1 2 3 4

TEA1114A

5 6 7 8

Fig.2 Pin configuration.

2000 Mar 21 5

MGK803

n.c.

15 14

MIC−

MIC+

GAR V

Philips Semiconductors Product speciﬁcation

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

FUNCTIONAL DESCRIPTION

All data given in this chapter are typical values, except when otherwise specified.

Supply (pins LN, SLPE, REG, VCCand VDD)

The supply for the TEA1114A and its peripherals is obtained from the telephone line (see Fig.3).

HE LINE INTERFACE (PINS LN, SLPE AND REG)

T The IC generates a stabilized reference voltage (V

between pins LN and SLPE. V

is temperature

ref

)

compensated and can be adjusted by means of an external resistor (RVA). V

equals 4.15 V and can be

ref

increased by connecting RVA between pins REG and SLPE or decreased by connecting R

between pins

REG and LN. The voltage at pin REG is used by the internal regulator to generate V C

, which is connected to VEE. This capacitor,

REG

and is decoupled by

ref

converted into an equivalent inductance (see Section “Set impedance”)realizesthesetimpedance conversion from its DC value (R

) to its AC value

SLPE

(RCCin the audio-frequency range). The voltage at pin SLPE is proportional to the line current.

The voltage at pin LN is:

SLPE

where:

line

ICC= current consumption of the IC IP= supply current for external circuits I

SUP

VDD regulator.

Thepreferredvalue for R 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 (V resistance (R line (R currents below 9 mA, the internal reference voltage (generatingV This means that more sets can operate in parallel with DC line voltages (excluding the polarity guard) down to an absolute minimum voltage of 1.45 V. At currents below 9 mA, the circuit has limited sending and receiving levels. This is called the low voltage area.

TEA1114A

ICC– IP– I

line

= line current

= current consumed between LN and VEE by the

EXCH

) and the reference voltage (V

line

ref

–

SUP

is 20 Ω.ChangingR

SLPE

), the feeding bridge

EXCH

SLPE

), the DC resistance of the telephone

). With line

ref

)isautomatically adjusted to a lower value.

will

handbook, full pagewidth

refRSLPE

EXCH

I×+

SLPE

line

TEA1114A

from preamplifier

REG SLPE

REG

4.7 µF

line

SLPE

20 Ω

SUP

REGULATOR

internal

circuitry

Fig.3 Supply configuration.

peripherals

VCC

100 µF

VDD

220 µF

external

circuits

MGK805

2000 Mar 21 6

Philips Semiconductors Product speciﬁcation

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 V voltage by means of a resistor (R decoupled by a capacitor C supply some external circuits. The V on the current consumed by the IC and the peripheral

circuits as:

(seealso Figs 4 and 5). I output stage of the earpiece amplifier.

. This voltage supply is derived from the line

) and must be

. It may also be used to

VCC

handbook, halfpage

CC0RCCIPIrec

CC0

VLNR

×–=

CCICC

+()×–=

isthe current consumed by the

rec

voltage depends

handbook, halfpage

(mA)

TEA1114A

1.9 mA

1.6 mA

12 43

(2) (1)

MGL827

VCC (V)

CC0

rec

EXTERNAL

CIRCUITS

MGK806

Fig.4 VCC used as supply voltage for external

circuits.

THE REGULATED SUPPLY POINT (PIN VDD) The V

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) consistsofa sense input circuit, a current switchandaV

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 constantwhiletheoutput(source)currentis determined by the consumption of the peripherals. The difference betweeninputand output current is shunted bytheinternal

stabilizer.

VCC≥ 2.5 V; VLN= 4.35 V at I

=20Ω.

SLPE

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

= 150 mV; RL1= 150 Ω.

QR(rms)

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

= 15 mA; RCC= 619 Ω;

line

Fig.5 Typical current IP available from VCC for

peripheral circuitry.

Inringer mode, the stabilizer operates as ashunt stabilizer to keep V

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 C

VDD

2000 Mar 21 7

Philips Semiconductors Product speciﬁcation

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

handbook, full pagewidth

EXCH

line

TEA1114A

line

SUP

SENSE

SWITCH

VDD regulator

TEA1114A

VCC

peripherals

220 µF

100 µF

VDD

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.

REG

× R

SLPE

× RP.

R 20 Ω

ref

SLPE

REG V

REG

4.7 µF

619 Ω

VCC

100 µF

MBE788

handbook, halfpage

LEQ=C RP= internal resistance. RP= 17.5 kΩ.

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). Thevoltage 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.

Fig.7 Equivalent impedance between LN and VEE.

2000 Mar 21 8

Philips Semiconductors Product speciﬁcation

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

Receiving stage (pins IR, RX, GAR and QR)

The receive part consists of a receive amplifier and an earpiece amplifier.

THE RECEIVE AMPLIFIER (PINS IR AND RX) The receive amplifier transfers the receive signal from

input IR to output RX. The input impedance of the receive amplifier, between pins IR and VEE,is20kΩ. The voltage gain from pin IR to RX is set at 33.4 dB. RX output is intended to drive high ohmic (real) loads. Automatic gain control is provided on the receive amplifier.

THE EARPIECE AMPLIFIER (PINS GAR AND QR) The earpiece amplifier is an operational amplifier having

its output (QR) and inverting input (GAR) available. It can be used in conjunction with two resistors to get someextra gain or attenuation.

In an usual configuration (see Fig.8), output RX drives the earpiece amplifier by means of RE1 connected between RX and GAR. Feedback resistor RE2 of the earpiece amplifier is connected between QR and GAR. Output QR drives the earpiece.

The gain of the earpiece amplifier (from RX to QR) can be set between +12 and −14 dB by means of resistor RE2.

The preferred value of RE1 is 100 kΩ. The earpiece amplifier offers a gain boost facility relative

to the initial gain. Resistor RE2 has to be replaced by the network of R

The initial gain is defined by: which corresponds to R

by a defined value of R

E21RE22

-------------------------------

Two external capacitors C and QR) and C ensure stability. The C low-pass filter. The cut-off frequency corresponds to the time constant C C

GARS

The output voltages of both amplifiers are specified for continuous wave drive. The maximum output swing depends on the DC line voltage V ICC current consumption of the circuit, the IP current consumption of the peripheral circuits and the load impedance.

=10×C

TEA1114A

, R

E21

×–

and R

E22

E23

E21



----------------------------------



(connected between GAR and VEE)

GARS

GAR

× RE2. The relationship

GAR

must be fulfilled to ensure stability.

GAR

as shown in Fig.8.

E23

E21RE22

–

------------------------------R

= ∞. The gain boost is realized

and is:

// R

E22

E23

(connected between GAR

GAR

capacitor provides a first-order

, the RCCresistor, the

handbook, full pagewidth

EXCH

line

TEA1114A

GAR

EARPIECE AMPLIFIER

0.5V

QRLN GAR

Fig.8 Earpiece amplifier configuration.

GARS

VCC

100 µF

GAR

Addition for gain boost of earpiece amplifier

100 kΩ

E21

10 µF

E22

GARS

E23

MGK808

2000 Mar 21 9

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