Philips TEA1110AT-C1, TEA1110A-C1 Datasheet

DATA SH EET

Product specification
Supersedes data of 1996 Nov 26
File under Integrated Circuits, IC03

1997 Apr 22

INTEGRATED CIRCUITS

TEA1110A

Low voltage versatile telephone
transmission circuit with dialler
interface

1997 Apr 22 2

Philips Semiconductors Product specification

Low voltage versatile telephone
transmission circuit with dialler interface

TEA1110A

FEATURES

• Low DC line voltage; operates down to 1.6 V (excluding
voltage drop over external polarity guard)

• Voltage regulator with adjustable DC voltage

• Provides a supply for external circuits

• Symmetrical high impedance inputs (64 kΩ) for

dynamic, magnetic or piezo-electric microphones

• Asymmetrical high impedance input (32 kΩ) for electret
microphones

• DTMF input with confidence tone

•

MUTE input for pulse or DTMF dialling

• Receiving amplifier for dynamic, magnetic or
piezo-electric earpieces

• AGC line loss compensation for microphone and
earpiece amplifiers.

APPLICATION

• Line powered telephone sets, cordless telephones, fax
machines, answering machines.

GENERAL DESCRIPTION

The TEA1110A 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 1.6 V DC (with reduced performance) to
facilitate the use of telephone sets connected in parallel.

All statements and values refer to all versions unless
otherwise specified.

QUICK REFERENCE DATA

I

line

= 15 mA; VEE=0V; R

SLPE

=20Ω; AGC pin connected to VEE; Z

line

= 600 Ω; f = 1 kHz; T

amb

=25°C;

unless otherwise specified.

ORDERING INFORMATION

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 3.35 3.65 3.95 V

I

CC

internal current consumption VCC= 2.9 V − 1.1 1.4 mA

V

CC

supply voltage for peripherals IP=0mA − 2.9 − V

G

vtrx

typical voltage gain

microphone amplifier (not adjustable) V

MIC

= 4 mV (RMS) − 43.7 − dB

receiving amplifier range V

IR

= 4 mV (RMS) 19 − 33 dB

∆G

vtrx

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

line

=15mA

I

line

=85mA − 5.9 − dB

∆G

vtrxm

gain reduction for microphone and
receiving amplifiers

MUTE = LOW − 80 − dB

TYPE

NUMBER

PACKAGE

NAME DESCRIPTION VERSION

TEA1110A DIP14 plastic dual in-line package; 14 leads (300 mil) SOT27-1
TEA1110AT SO14 plastic small outline package; 14 leads; body width 3.9 mm SOT108-1

1997 Apr 22 3

Philips Semiconductors Product specification

Low voltage versatile telephone
transmission circuit with dialler interface

TEA1110A

BLOCK DIAGRAM

handbook, full pagewidth

ATT.

DTMF

AGC

CIRCUIT

CURRENT

REFERENCE

LOW VOLTAGE

CIRCUIT

IR

MIC+

MIC−

V

EE

AGC

SLPE

TEA1110A(T)

3

2811

9

10

13 12 6

14

1

5

7

GAR

QR MUTE

LN

V

CC

REG

V I

MGG736

V I

V I

V I

Fig.1 Block diagram.

1997 Apr 22 4

Philips Semiconductors Product specification

Low voltage versatile telephone
transmission circuit with dialler interface

TEA1110A

PINNING

SYMBOL PIN DESCRIPTION

LN 1 positive line terminal
SLPE 2 slope (DC resistance) adjustment
REG 3 line voltage regulator decoupling
n.c. 4 not connected
DTMF 5 dual-tone multi-frequency input
MUTE 6 mute input to select speech or

dialling mode (active LOW)
IR 7 receiving amplifier input
AGC 8 automatic gain control/

line loss compensation
MIC− 9 inverting microphone amplifier input
MIC+ 10 non-inverting microphone amplifier

input
V

EE

11 negative line terminal
QR 12 receiving amplifier output
GAR 13 receive gain adjustment
V

CC

14 supply voltage for speech circuit and

peripherals

Fig.2 Pin configuration.

handbook, halfpage

MGG735

TEA1110A(T)

1
2
3
4
5
6
7

8

14
13
12
11
10

9

LN

SLPE

REG

n.c.
DTMF
MUTE

IR

AGC

MIC−

MIC+

V

EE

QR

GAR

V

CC

FUNCTIONAL DESCRIPTION

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

Supply (pins LN, SLPE, V

CC

and REG)

The supply for the TEA1110A and its peripherals is
obtained from the telephone line. See Fig.3.

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 3.35 V and can be
increased by connecting RVA between pins REG
and SLPE (see Fig.4), 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 into an equivalent inductance
(see Section “Set impedance”), realizes the set
impedance conversion from its DC value (R

SLPE

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

The voltage at pin LN is:

Where:

I

line

= line current
ICC= current consumption of the IC
IP= supply current for peripheral circuits
I* = current consumed between LN and VEE.

The preferred value for R

SLPE

is 20 Ω. Changing R

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.

V

LN

V

refRSLPEISLPE

×+=

I

SLPEIlineICC

– IP– I∗–=

1997 Apr 22 5

Philips Semiconductors Product specification

Low voltage versatile telephone
transmission circuit with dialler interface

TEA1110A

Fig.3 Supply configuration.

handbook, full pagewidth

I

SLPE

I

sh

REG

311

LN
114

from pre amp

SLPE

2

V

EE

V

d

V

CC

R

CC

C

VCC

I

CC

C

REG

R

SLPE

V

exch

R

exch

I

line

R

line

TEA1110A

I*

I

P

peripheral

circuits

100 µF

4.7 µF

20 Ω

619 Ω

MGG737

The internal circuitry of the TEA1110A is supplied from
pin VCC. This voltage supply is derived from the line
voltage by means of a resistor (R

CC

) and must be

decoupled by a capacitor C

VCC

. It may also be used to
supply peripheral circuits such as dialling or control
circuits. The V

CC

voltage depends on the current
consumed by the IC and the peripheral circuits as shown
by the formula:

(see also Figs 5 and 6).

R

CCint

is the internal equivalent resistance of the voltage

supply, and I

rec

is the current consumed by the output

stage of the earpiece amplifier.
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 7.5 mA, the internal reference voltage (generating
V

ref

) is automatically 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 1.6 V. At currents below 7.5 mA, the
circuit has limited sending and receiving levels. This is
called the low voltage area.

V

CC

V

CC0RCCintIPIrec

–()×–=

V

CC0

VLNR

CCICC

×–=

Fig.4 Reference voltage adjustment by RVA.

(1) Influence of RVA on V

ref

.

(2) V

ref

without influence of RVA.

handbook, halfpage

6.0

V

ref

(V)

3.0

4.0

(1)

(2)

5.0

RVA (Ω)

MGD176

10

5

10

4

10

6

10

7

1997 Apr 22 6

Philips Semiconductors Product specification

Low voltage versatile telephone
transmission circuit with dialler interface

TEA1110A

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.

Microphone amplifier (pins MIC+ and MIC−)

The TEA1110A has symmetrical microphone inputs.
The input impedance between pins MIC+ and MIC− is
64 kΩ (2 × 32 kΩ). The voltage gain from pins MIC+/MIC−
to pin LN is set at 43.7 dB (typ).

Automatic gain control is provided on this amplifier for line
loss compensation.

Receiving amplifier (pins IR, GAR and QR)

The receiving amplifier has one input (IR) and one output
(QR). The input impedance between pin IR and pin V

EE

is
20 kΩ. The voltage gain from pin IR to pin QR is set at
33 dB (typ). The gain can be decreased by connecting an
external resistor R

GAR

between pins GAR and QR; the

adjustment range is 14 dB. 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

× (R

GARint

// R

GAR

). R

GARint

is the internal resistor
which sets the gain with a typical value of 125 kΩ.
The condition C

GARS

=10×C

GAR

must be fulfilled to

ensure stability.
The output voltage of the receiving amplifier is specified for

continuous wave drive. The maximum output swing
depends on the DC line voltage, the RCC resistor, the I

CC

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

Automatic gain control is provided on this amplifier for line
loss compensation.

Automatic gain control (pin AGC)

The TEA1110A performs automatic line loss
compensation. The automatic gain control varies the gain
of the microphone amplifier and the gain of the receiving
amplifier in accordance with the DC line current.
The control range is 5.9 dB (which corresponds
approximately to a line length of 5 km for a 0.5 mm
diameter twisted-pair copper cable with a DC resistance of
176 Ω/km and an average attenuation of 1.2 dB/km).
The IC can be used with different configurations of feeding
bridge (supply voltage and bridge resistance) by
connecting an external resistor R

AGC

between pins AGC

and V

EE

. This resistor enables the I

start

and I

stop

line

currents to be increased (the ratio between I

start

and I

stop

is
not affected by the resistor). The AGC function is disabled
when pin AGC is left open-circuit.

Mute function (pin

MUTE)

The mute function performs the switching between the
speech mode and the dialling mode. WhenMUTE is LOW,
the DTMF input is enabled and the microphone and
receiving amplifiers inputs are disabled. When MUTE is
HIGH, the microphone and receiving amplifiers inputs are
enabled while the DTMF input is disabled. A pull-up
resistor is included at the input.

DTMF amplifier (pin DTMF)

When the DTMF amplifier is enabled, dialling tones may
be sent on line. These tones can be heard in the earpiece
at a low level (confidence tone).

The TEA1110A has an asymmetrical DTMF input.
The input impedance between DTMF and V

EE

is 20 kΩ.

The voltage gain from pin DTMF to pin LN is 25.3 dB.
The automatic gain control has no effect on the DTMF

amplifier.

Fig.5 Typical current IP available from VCC for

peripheral circuits at I

line

= 15 mA.

(1) With RVA resistor.
(2) Without RVA resistor.

handbook, halfpage

2.5

0

01234

MBE783

0.5

1

1.5

2

VCC (V)

(1)(2)

I

P

(mA)