Philips TEA1110AT, TEA1110A Datasheet

INTEGRATED CIRCUITS

DATA SH EET

TEA1110A

Low voltage versatile telephone transmission circuit with dialler interface

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

1997 Apr 22

Philips Semiconductors Product speciﬁcation

Low voltage versatile telephone transmission circuit with dialler interface

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.

QUICK REFERENCE DATA

= 15 mA; VEE=0V; R

line

=20Ω; AGC pin connected to VEE; Z

SLPE

unless otherwise speciﬁed.

APPLICATION

• Line powered telephone sets, cordless telephones, fax

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.

machines, answering machines.

= 600 Ω; f = 1 kHz; T

line

amb

TEA1110A

=25°C;

SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT

line

line current operating range normal operation 11 − 140 mA

with reduced performance 1 − 11 mA V I

V G

∆G

vtrx

DC line voltage 3.35 3.65 3.95 V internal current consumption VCC= 2.9 V − 1.1 1.4 mA supply voltage for peripherals IP=0mA − 2.9 − V typical voltage gain

microphone amplifier (not adjustable) V receiving amplifier range V

gain control range for microphone and

= 4 mV (RMS) − 43.7 − dB

MIC

= 4 mV (RMS) 19 − 33 dB

=85mA − 5.9 − dB

line

receiving ampliﬁers with respect to I

=15mA

line

∆G

vtrxm

gain reduction for microphone and

MUTE = LOW − 80 − dB

receiving ampliﬁers

ORDERING INFORMATION

TYPE

NUMBER

NAME DESCRIPTION VERSION

PACKAGE

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 2

Philips Semiconductors Product speciﬁcation

Low voltage versatile telephone transmission circuit with dialler interface

BLOCK DIAGRAM

handbook, full pagewidth

DTMF

ATT.

V I

GAR

QR MUTE

13 12 6

CURRENT

REFERENCE

TEA1110A

MIC+

MIC−

V I

AGC

CIRCUIT

AGC

LOW VOLTAGE

CIRCUIT

TEA1110A(T)

2811 SLPE

REG

MGG736

Fig.1 Block diagram.

1997 Apr 22 3

Philips Semiconductors Product speciﬁcation

Low voltage versatile telephone transmission circuit with dialler interface

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

QR 12 receiving ampliﬁer output GAR 13 receive gain adjustment V

11 negative line terminal

14 supply voltage for speech circuit and

peripherals

handbook, halfpage

SLPE

2 3

REG

n.c.

TEA1110A(T)

DTMF

MUTE

MGG735

Fig.2 Pin configuration.

TEA1110A

GAR

MIC+

MIC−

AGC

FUNCTIONAL DESCRIPTION

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

Supply (pins LN, SLPE, V

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 between pins LN and SLPE. V

is temperature

ref

)

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

equals 3.35 V and can be

ref

increased by connecting RVA between pins REG and SLPE (see Fig.4), or decreased by connecting R

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

, which is connected to VEE. This

REG

and is

ref

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:

V I

SLPEIlineICC

refRSLPEISLPE

– IP– I∗–=

×+=

Where:

= line current

line

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

The preferred value for R

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.

1997 Apr 22 4

Philips Semiconductors Product speciﬁcation

Low voltage versatile telephone transmission circuit with dialler interface

handbook, full pagewidth

exch

line

SLPE

LN 114

2 SLPE

SLPE

20 Ω

619 Ω

from pre amp

VCC

100 µF

TEA1110A

311

REG

4.7 µF

TEA1110A

peripheral

circuits

MGG737

Fig.3 Supply configuration.

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 decoupled by a capacitor C

VCC

) and must be

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

voltage depends on the current

consumed by the IC and the peripheral circuits as shown by the formula:

V V

R supply, and I

CC0

CCint

CC0RCCintIPIrec

VLNR

×–=

CCICC

is the internal equivalent resistance of the voltage

is the current consumed by the output

rec

–()×–=

(see also Figs 5 and 6).

stage of the earpiece amplifier. The DC line current flowing into the set is determined by

the exchange supply voltage (V resistance (R (R

) and the reference voltage (V

line

), the DC resistance of the telephone line

exch

), the feeding bridge

exch

). With line currents

ref

below 7.5 mA, the internal reference voltage (generating V

) is automatically adjusted to a lower value. This means

ref

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.

6.0

handbook, halfpage

ref

(V)

5.0

4.0

(1)

(2)

3.0

(1) Influence of RVA on V (2) V

without influence of RVA.

ref

Fig.4 Reference voltage adjustment by RVA.

RVA (Ω)

MGD176

1997 Apr 22 5

Philips Semiconductors Product speciﬁcation

Low voltage versatile telephone transmission circuit with dialler interface

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 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

between pins GAR and QR; the

GAR

adjustment range is 14 dB. Two external capacitors C (connected between GAR and QR) and C between GAR and VEE) ensure stability. The C

GARS

(connected

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

is the internal resistor

GARint

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

GARS

=10×C

must be fulfilled to

GAR

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

GAR

TEA1110A

and V currents to be increased (the ratio between I not affected by the resistor). The AGC function is disabled when pin AGC is left open-circuit.

Mute function (pin

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 The voltage gain from pin DTMF to pin LN is 25.3 dB.

The automatic gain control has no effect on the DTMF amplifier.

handbook, halfpage

. This resistor enables the I

MUTE)

2.5

(mA)

1.5

start

and I

line

stop

and I

start

is 20 kΩ.

MBE783

stop

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

between pins AGC

AGC

1997 Apr 22 6

0.5

01234

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

(1)(2)

VCC (V)

Fig.5 Typical current IP available from VCC for

peripheral circuits at I

= 15 mA.

line

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