Philips TEA1114AT, TEA1114A Datasheet

INTEGRATED CIRCUITS

DATA SH EET

TEA1114A

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

Product specification
Supersedes data of 1998 Jun 12
File under Integrated Circuits, IC03

1999 Sep 14

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

NAME DESCRIPTION VERSION

PACKAGE

1999 Sep 14 2

Philips Semiconductors Product specification

Low voltage telephone transmission circuit with

TEA1114A

dialler interface and regulated strong supply

QUICK REFERENCE DATA

I

= 15 mA; VEE=0V;R

line

circuits given in Figs 14, 15 and 16; T

SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT

I

V
I
V

line

LN

CC

CC

line current operating range normal operation 11 − 140 mA

DC line voltage 4.05 4.35 4.65 V
internal current consumption VCC= 3.7 V − 1.25 1.5 mA
supply voltage for internal circuitry

(unregulated)

V

DD

regulated supply voltage for peripherals

speech mode I
ringer mode I

I

DD

G

v(TX)

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

amplifier

G

∆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; unless otherwise specified.

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

DD

= 75 mA 3.0 3.3 3.6 V

DD

V

= 4 mV (RMS) 43.2 44.2 45.2 dB

MIC

I

=85mA − 6.0 − dB

line

MUTE = LOW − 80 − dB

1999 Sep 14 3

Philips Semiconductors Product specification

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

BLOCK DIAGRAM

handbook, full pagewidth

48IR

VI

MUTE

VI

6DTMF

ATTENUATOR

0.5V

CC

TEA1114A

1211RX

GAR

9QR

CURRENT AND

VOLTAGE

REFERENCE

MIC+
MIC−

V

EE

AGC

VI

V

DD

REGULATOR

V

16

CC

V

7

DD

TEA1114A

13

VI

14

10

AGC

CIRCUIT

LOW VOLTAGE

5

CIRCUIT

SLPE

1LN

3 REG

2

MGK804

Fig.1 Block diagram.

1999 Sep 14 4

Philips Semiconductors Product specification

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

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
V

DD

7 regulated supply for peripherals

MUTE 8 mute input to select speech or

dialling mode (active LOW)
QR 9 earpiece amplifier output
V

EE

10 negative line terminal
GAR 11 earpiece amplifier inverting input
RX 12 receive amplifier output
MIC+ 13 non-inverting microphone amplifier

input
MIC− 14 inverting microphone amplifier input
n.c. 15 not connected
V

CC

16 supply voltage for internal circuit

handbook, halfpage

LN

1

SLPE

2
3

REG

IR

4

TEA1114A

5

AGC

DTMF

6

V

7

DD

8

MUTE

MGK803

Fig.2 Pin configuration.

TEA1114A

V

16

CC

n.c.

15
14

MIC−

13

MIC+

12

RX

11

GAR
V

10

EE

QR

9

1999 Sep 14 5

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

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

VA

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

, which is connected to VEE.

REG

and is decoupled by

ref

This capacitor, converted into an equivalent inductance
(seeSection “Set impedance”) realizes the set impedance
conversion from its DC value (R

) to its AC value (R

SLPE

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

The voltage at pin LN is:

I

SLPE

where:

I

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

CC

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

I=

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

V

=

V

LN

handbook, full pagewidth

refRSLPE

R

EXCH

V

EXCH

I×+

SLPE

R

line

TEA1114A

from preamplifier

REG SLPE

C

REG

4.7 µF

I

line

I

SLPE

R

CC

I

LN

LN

R

20 Ω

I

SUP

SLPE

V

DD

REGULATOR

V

CC

internal
circuitry

V

EE

Fig.3 Supply configuration.

I

V

CC

DD

I

DD

peripherals

C

VCC

100 µF

C

VDD

220 µF

external

circuits

MGK805

I

P

1999 Sep 14 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:

V

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

. This voltage supply is derived from the line

CC

) and must be

CC

. It may also be used to

VCC

V

CC

handbook, halfpage

CC0RCCIPIrec

CC0

R

CC

VLNR

V

V

×–=

CCICC

+()×–=

isthe current consumed by the

rec

CC

voltage depends

CC

handbook, halfpage

(mA)

TEA1114A

3

I

P

1.9 mA

2

1.6 mA

1

0

0

12 43

(2) (1)

MGL827

VCC (V)

V

CC0

I

rec

V

EE

EXTERNAL

CIRCUITS

I

P

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

DD

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

DD

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.

V

DD

VCC≥ 2.5 V; VLN= 4.35 V at I

=20Ω.

R

SLPE

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

= 150 mV; RL1= 150 Ω.

V

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

DD

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

.

1999 Sep 14 7

Philips Semiconductors Product specification

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

handbook, full pagewidth

R

EXCH

V

EXCH

R

line

TEA1114A

I

LN

line

I

I

LN

SUP

SENSE

R

CC

I

CC

V

CC

SWITCH

VDD regulator

TEA1114A

C

VCC

V

DD

I

DD

peripherals

C

V

EE

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

V

LN

SLPE

EE

SLPE

× RP.

L

EQ

V

R
20 Ω

ref

SLPE

R

P

REG V

C

REG

4.7 µF

R

CC

619 Ω

CC

C

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.

1999 Sep 14 8