Philips TEA1111AT-C1 Datasheet

DATA SH EET

Product specification
Supersedes data of 1999 Sep 28
File under Integrated Circuits, IC03

1999 Nov 22

INTEGRATED CIRCUITS

TEA1111A

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

1999 Nov 22 2

Philips Semiconductors Product specification

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

TEA1111A

FEATURES

• Low DC linevoltage; operates down to 1.5 V (excluding
voltage drop across external polarity guard)

• Line voltage regulator with adjustable DC voltage

• 3.25 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 earpiece.

• Receive stage with:
– Earpiece amplifier with adjustable gain and volume

control.

• MUTE input for pulse or DTMF dialling

• AGC line loss compensation for microphone and

earpiece

• LED control output.

APPLICATIONS

• Line powered telephone sets with LCD module

• Cordless telephones

• Fax machines

• Answering machines.

GENERAL DESCRIPTION

The TEA1111A 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 1.5 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 3.25 V to supply peripherals such as dialler,
LCD module and microcontroller.

QUICK REFERENCE DATA

I

line

= 15 mA; VEE=0V; V

VCI

=0V; R

SLPE

=20Ω; AGC pin connected to VEE; Z

line

= 600 Ω; f = 1 kHz; measured

according to test circuits given in Figs 14, 15 and 16; T

amb

=25°C; unless otherwise specified.

SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT

I

line

line current operating range normal operation 11 − 140 mA

with reduced
performance

1 − 11 mA

V

LN

DC line voltage 3.7 4.0 4.3 V

I

CC

internal current consumption VCC= 3.3 V − 1.15 1.4 mA

V

CC

supply voltage for internal circuitry (unregulated) IP=0mA − 3.3 − V

V

DD

regulated supply voltage for peripherals

speech mode I

DD

= −3 mA 2.95 3.25 3.55 V

ringer mode I

DD

= 75 mA 3.0 3.3 3.6 V

I

DD

available supply current for peripherals −−−3mA

G

v(TX)

typical voltage gain for microphone amplifier V

MIC

= 4 mV (RMS) 43.2 44.2 45.2 dB

G

v(QR)

typical voltage gain for earpiece amplifier VIR= 4 mV (RMS) 26.4 27.4 28.4 dB

∆G

v(QR)

volume control range for earpiece amplifier 0 14.5 − dB

∆G

v(trx)

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

line

=15mA

I

line

=85mA − 6.0 − dB

∆G

v(trx)(m)

gain reduction for microphone and earpiece
amplifiers

MUTE = LOW − 80 − dB

1999 Nov 22 3

Philips Semiconductors Product specification

Speech circuit withdialler interface,regulated
supply and earpiece volume control

TEA1111A

ORDERING INFORMATION

BLOCK DIAGRAM

TYPE

NUMBER

PACKAGE

NAME DESCRIPTION VERSION

TEA1111AT SO16 plastic small outline package; 16 leads; body width 3.9 mm SOT109-1

handbook, full pagewidth

FCA051

VI

VI

VI

VI

CURRENT AND

VOLTAGE

REFERENCE

microphone

amplifier

receive

amplifier

earpiece
amplifier

LOW VOLTAGE

CIRCUIT

AGC

CIRCUIT

VOLUME

CONTROL

V

DD

REGULATOR

ATTENUATOR

0.5V

CC

TEA1111A

4

8

IR

MUTE

13
14

MIC+

6

DTMF

MIC−

10

5

V

EE

AGC

129

11

GARVCI

QR

1

LN

7

V

DD

16

V

CC

SLPELEDCREG

2

153

LED CONTROL

Fig.1 Block diagram.

1999 Nov 22 4

Philips Semiconductors Product specification

Speech circuit withdialler interface,regulated
supply and earpiece volume control

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
V

DD

7 regulated supply for peripherals

MUTE 8 mute input to select speech or

dialling mode (active LOW)
VCI 9 volume control input
V

EE

10 negative line terminal
QR 11 earpiece amplifier output
GAR 12 earpiece amplifier gain adjustment
MIC+ 13 non-inverting microphone amplifier

input
MIC− 14 inverting microphone amplifier input
LEDC 15 LED control output
V

CC

16 supply voltage for internal circuit

handbook, halfpage

TEA1111A

FCA052

1
2
3
4
5
6
7
8

16
15
14
13
12
11
10

9

LN

SLPE

REG

IR

AGC

DTMF

V

DD

MUTE

VCI

V

EE

QR

GAR

MIC+

MIC−

V

CC

LEDC

Fig.2 Pin configuration.

FUNCTIONAL DESCRIPTION

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

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

The supply for the TEA1111A and its peripherals is
obtained from the telephone line (see Fig.3).

T

HE LINE INTERFACE (PINS LN, SLPE AND REG)

The IC generates a stabilized reference voltage (V

ref

)

across pins LN and SLPE. V

ref

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

ref

equals 3.8 V and can be increased by
connecting RVA between pins REG and SLPE or
decreased by connecting R

VA

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

ref

and is decoupled by C

REG

, 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 (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:
V

LN=Vref+RSLPE

× I

SLPE

I

SLPE=Iline

− ICC− IP− I

SUP

− I

LEDC

where:

I

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
I

LEDC

= supply current for external LED circuitry.

Thepreferredvaluefor 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 I

low

(9 mA), the internal reference voltage

(generatingV

ref

)isautomaticallyadjusted to a lower value.

1999 Nov 22 5

Philips Semiconductors Product specification

Speech circuit withdialler interface,regulated
supply and earpiece volume control

TEA1111A

This means that several sets can operate in parallel with
DC line voltages (excluding the polarity guard) down to an
absolute minimum voltage of 1.5 V. At line currents below
I

low

, the circuit has limited sending and receiving levels.

This is called the low voltage area.

THE INTERNAL SUPPLY POINT (PIN VCC)
The internal circuitry of the TEA1111A is supplied from

pin V

CC

. This voltage supply is derived from the line
voltage by means of a resistor (RCC) and must be
decoupled by a capacitor C

VCC

. It may also be used to

supply some external circuits.

The V

CC

voltage (see also Figs 4 and 5) depends on the

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

CC0=VLN

− RCC× I

CC

VCC=V

CC0

− RCC× (IP+I

rec

)

Where I

rec

is the current consumed by the output stage of

the earpiece amplifier.

handbook, full pagewidth

C

REG

4.7 µF

R

SLPE

20 Ω

I

SLPE

FCA053

I

line

I

LEDC

R

line

V

CC

V

EE

REGSLPE

LN

LEDC

V

DD

C

VCC

100 µF

C

VDD

220 µF

TEA1111A

R

CC

I

CC

I

LN

I

P

I

DD

I

SUP

R

EXCH

V

EXCH

peripherals

external

circuits

from preamplifier

V

DD

REGULATOR

internal

circuitry

LED

CONTROL

LED

CIRCUIT

Fig.3 Supply configuration.

1999 Nov 22 6

Philips Semiconductors Product specification

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

TEA1111A

handbook, halfpage

MGK806

I

rec

EXTERNAL

CIRCUITS

I

P

V

EE

V

CC

V

CC0

R

CC

Fig.4 VCC used as supply voltage for external circuits.

handbook, halfpage

2.2 2.6 3.4

2

0

1.6

FCA054

3.0

1.2

0.8

0.4

(1) (2)

I

P

(mA)

VCC (V)

Fig.5 Typical current IP available from VCC for peripheral circuitry.

VCC≥ 2.2 V; VLN= 4 V at I

line

= 15 mA; RCC= 619 Ω; R

SLPE

=20Ω.

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

QR(rms)

= 150 mV; RL= 150 Ω.

(2) Curve 2 is valid when the earpiece amplifier is not loaded.

1999 Nov 22 7

Philips Semiconductors Product specification

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

TEA1111A

THE REGULATED SUPPLY POINT (PIN VDD)
The V

DD

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 fed by pin LN, a current
switch and a V

DD

output stabilizer.

Theregulatorfunctiondependsonthetransmission,ringer
and trickle modes as follows:

• Transmissionmode:Theregulatoroperatesasacurrent

source at the LN input; it takes a constant current of
I

SUP

= 4.3 mA (at nominal conditions) from pin LN.
The current switch reduces the distortion on the line at
large signal swings. Output V

DD

follows the DC voltage
at pin LN (with typically 0.35 V difference) up to
VDD= 3.25 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 currents is shunted by the
internal VDD stabilizer.

• Ringer mode: The regulator operates as a shunt
stabilizer to keep V

DD

at 3.3 V. The input voltage
VLNequals 0 V while the input current into pin VDD is
delivered by the ringingsignal. VDDhas to be decoupled
by a capacitor C

VDD

.

• Trickle mode: When VDD is below 2 V, the regulator is
inhibited. The current consumption of the VDDregulator
in trickle mode is very low to save most of the trickle
current for memory retention of a dialler.

handbook, full pagewidth

FCA055

I

line

R

line

V

CC

V

EE

LN

V

DD

C

VCC

100 µF

C

VDD

220 µF

TEA1111A

R

CC

I

CC

I

LN

R

EXCH

V

EXCH

peripherals

SENSE

SWITCH

VDD regulator

I

SUP

I

DD

Fig.6 VDD regulator configuration.

1999 Nov 22 8

Philips Semiconductors Product specification

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

TEA1111A

LED control (pin LEDC)

The TEA1111A gives an on-hook/off-hook status
indication. This is achieved by a current made available at
pin LEDC to drive an external LED circuit connected
between pins SLPE and LN (see Fig.7). In the low voltage
area, which corresponds to low line current conditions, no
current is available for this LED. For line currents higher
than a threshold, the LEDC current increases
proportionally to the line current (with a ratio of 1:150).
The LEDC current is internally limited to 470 µA
(see Fig.8).

For 12 mA < I

line

< 82 mA:

This LED circuit is referenced to SLPE. Consequently, all
theLEDsupply current will flow through the R

SLPE

resistor,

and does not affect the behaviour of the AGC.

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.9.

I

LEDC

I

line

12–

150

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

=

FCA056

2.4
kΩ

24

Ω

BC858B

LN

LEDC

SLPE

Fig.7 LED circuit configuration.

handbook, halfpage

0 20 40 100

500

0

400

FCA057

60 80

300

200

100

I

LEDC

(µA)

I

line

(mA)

Fig.8 LEDC current versus line current.

handbook, halfpage

LN

V

EE

SLPE

R

SLPE

C

REG

REG V

CC

R

CC

4.7 µF

100 µF

C

VCC

619 Ω

20 Ω

R

P

V

ref

L

EQ

MBE788

Fig.9 Equivalent impedance between LN and VEE.

LEQ=C

REG

× R

SLPE

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