Philips TEA1114AT-C2, TEA1114AT-C1, TEA1114A-C2, TEA1114A-C1 Datasheet

DATA SH EET

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

2000 Mar 21

INTEGRATED CIRCUITS

TEA1114A

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

2000 Mar 21 2

Philips Semiconductors Product speciﬁcation

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

TEA1114A

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.

ORDERING INFORMATION

TYPE

NUMBER

PACKAGE

NAME DESCRIPTION VERSION

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 −

2000 Mar 21 3

Philips Semiconductors Product speciﬁcation

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

TEA1114A

QUICK REFERENCE DATA

line

= 15 mA; VEE=0V;R

SLPE

=20Ω;AGC pin connected to VEE;Z

line

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

circuits given in Figs 15, 16 and 17; T

amb

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

speciﬁed.

SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT

line

line current operating range normal operation 11 − 140 mA

with reduced performance 1 − 11 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)

IP=0mA − 3.6 − V

regulated supply voltage for peripherals

speech mode I

= −3 mA 3.0 3.3 3.6 V

ringer mode I

= 75 mA 3.0 3.3 3.6 V

available supply current for peripherals −−−3mA

v(TX)

typical voltage gain for microphone ampliﬁer

MIC

= 4 mV (RMS) 43.2 44.2 45.2 dB

v(RX)

typical voltage gain for receiving ampliﬁer VIR= 4 mV (RMS) 32.4 33.4 34.4 dB

∆G

v(QR)

gain setting range for earpiece ampliﬁer RE1= 100 kΩ−14 − +12 dB

∆G

v(trx)

gain control range for microphone and receive ampliﬁers with respect to I

line

=15mA

line

=85mA − 6.0 − dB

∆G

v(trx)(m)

gain reduction for microphone and receive ampliﬁers

MUTE = LOW − 80 − dB

2000 Mar 21 4

Philips Semiconductors Product speciﬁcation

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

TEA1114A

BLOCK DIAGRAM

handbook, full pagewidth

MGK804

CURRENT AND

VOLTAGE

REFERENCE

LOW VOLTAGE

CIRCUIT

AGC

CIRCUIT

REGULATOR

ATTENUATOR

0.5V

TEA1114A

48IR

MUTE

13 14

MIC+

6DTMF

MIC−

AGC

1211RX

GAR

9QR

3 REG

1LN

SLPE

Fig.1 Block diagram.

2000 Mar 21 5

Philips Semiconductors Product speciﬁcation

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

TEA1114A

PINNING

SYMBOL

PIN PAD

DESCRIPTION

TEA1114A(T) TEA1114AUH

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

7 7 regulated supply for peripherals 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

10 11 negative line terminal 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

16 17 supply voltage for internal circuit n.c. − 18 not connected

handbook, halfpage

TEA1114A

MGK803

1 2 3 4 5 6 7 8

16 15 14 13 12 11 10

SLPE

REG

AGC

DTMF

MUTE

GAR

MIC+

MIC−

n.c.

Fig.2 Pin configuration.

2000 Mar 21 6

Philips Semiconductors Product speciﬁcation

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

TEA1114A

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)

The IC generates a stabilized reference voltage (V

ref

)

between pins LN and SLPE. V

ref

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

ref

equals 4.15 V and can be 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

ref

and is decoupled by

REG

, which is connected to VEE. This capacitor, converted into an equivalent inductance (see Section “Set impedance”)realizesthesetimpedance conversion from its DC value (R

SLPE

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

The voltage at pin LN is:

where:

line

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

SUP

= current consumed between LN and VEE by the

VDD regulator.

Thepreferredvalue for R

SLPE

is 20 Ω.ChangingR

SLPE

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 (V

EXCH

), the feeding bridge

resistance (R

EXCH

), the DC resistance of the telephone

line (R

line

) and the reference voltage (V

ref

). With line currents below 9 mA, the internal reference voltage (generatingV

ref

)isautomatically adjusted to a lower value. 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.

refRSLPE

I×+

SLPE

line

ICC– IP– I

SUP

–

handbook, full pagewidth

REG

4.7 µF

SLPE

20 Ω

SLPE

MGK805

line

REG SLPE

VCC

100 µF

VDD

220 µF

TEA1114A

SUP

EXCH

peripherals

external

circuits

from preamplifier

REGULATOR

internal

circuitry

Fig.3 Supply configuration.

2000 Mar 21 7

Philips Semiconductors Product speciﬁcation

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

TEA1114A

THE INTERNAL SUPPLY POINT (PIN VCC) The internal circuitry of the TEA1114A is supplied from

pin V

. This voltage supply is derived from the line

voltage by means of a resistor (R

) and must be

decoupled by a capacitor C

VCC

. It may also be used to

supply some external circuits. The V

voltage depends

on the current consumed by the IC and the peripheral circuits as:

(seealso Figs 4 and 5). I

rec

isthe current consumed by the

output stage of the earpiece amplifier.

CC0

VLNR

CCICC

×–=

CC0RCCIPIrec

+()×–=

handbook, halfpage

MGK806

rec

EXTERNAL

CIRCUITS

CC0

Fig.4 VCC used as supply voltage for external

circuits.

handbook, halfpage

12 43

MGL827

(mA)

VCC (V)

(2) (1)

1.9 mA

1.6 mA

Fig.5 Typical current IP available from VCC for

peripheral circuitry.

VCC≥ 2.5 V; VLN= 4.35 V at I

line

= 15 mA; RCC= 619 Ω;

SLPE

=20Ω.

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

QR(rms)

= 150 mV; RL1= 150 Ω.

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

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 V

stabilizer.

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 8

Philips Semiconductors Product speciﬁcation

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

TEA1114A

handbook, full pagewidth

MGK807

line

VCC

100 µF

VDD

220 µF

TEA1114A

EXCH

peripherals

SENSE

SWITCH

VDD regulator

SUP

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.

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.

handbook, halfpage

SLPE

REG

REG V

4.7 µF

100 µF

VCC

619 Ω

20 Ω

ref

MBE788

Fig.7 Equivalent impedance between LN and VEE.

LEQ=C

REG

× R

SLPE

× RP. RP= internal resistance. RP= 17.5 kΩ.

2000 Mar 21 9

Philips Semiconductors Product speciﬁcation

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

TEA1114A

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

E21

, R

E22

and R

E23

as shown in Fig.8. The initial gain is defined by: which corresponds to R

E23

= ∞. The gain boost is realized

by a defined value of R

E23

and is:

Two external capacitors C

GAR

(connected between GAR

and QR) and C

GARS

(connected between GAR and VEE)

ensure stability. The C

GAR

capacitor provides a first-order low-pass filter. The cut-off frequency corresponds to the time constant C

GAR

× RE2. The relationship

GARS

=10×C

GAR

must be fulfilled to ensure stability.

The output voltages of both amplifiers are specified for continuous wave drive. The maximum output swing depends on the DC line voltage V

, the RCCresistor, the ICC current consumption of the circuit, the IP current consumption of the peripheral circuits and the load impedance.

E21RE22

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

–

E21RE22

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

E21

// R

E22

E23

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





×–

handbook, full pagewidth

MGK808

line

0.5V

QRLN GAR

GAR

GARS

VCC

100 µF

10 µF

EARPIECE AMPLIFIER

TEA1114A

EXCH

E23

E21

100 kΩ

E22

GAR

Addition for gain boost of earpiece amplifier

GARS

Fig.8 Earpiece amplifier configuration.

+ 19 hidden pages