SGS Thomson Microelectronics TEA7089A Datasheet

LOW-RANGE PHONE DEDICATED CHIP

.

RING

- GENERATION OF 8 MELODYTONES
(Includingthe 3 GermanMelody Tones)

- 4 STEPS DIGITAL CONTROL ON THE AM­PLIFIEROUTPUT LEVEL

.

SPEECH

- TRANSM I TGAINEXTERN ALLYADJUST ABL E

- RECEIV IN GGAINEXTER NALLYADJUSTA B LE

- AGCSLOPEEXTERN A LLYPROGRAMM ABLE

- SOFTCLIPPINGON SENDING CHANNEL

- RECEIVE AMPLIFIER FOR PIEZO OR
ELECTRODYNAMIC TRANSDUCER

- +6dB MODE ON RECEIVECHANNEL

- LINE POWER MANAGEMENT

.

DIALING

- DTMF GENERATOR

- LOW DC MASK DURING MAKE PERIOD
THROUGH MICROCONTROLLER SERIAL
BUS INTERFACE

.

MICROCONTROLLER INTERFACE

- 1.79MHzCLOCKOR3.58MHzOSCILLATOR
INPUT

.

MICROCONTROLLER POWER SUPPLY

.

MICROCONTROLLER CONTROL INTER­FACE INCLUDING SERIALBUS

.

LINE CURRENT EXTRACTOR FOR SUPPLY
OF EXTERNAL PERIPHERALS

(Plastic Package)

ORDER CODE : TEA7089AFP

PIN CONNECTIONS

SOFT

RECIN

SN

AGC

1
2
3
4

TEA7089A

SO28

28
27
26
25

DTMF

V

REF

V

RMC

DCL

DESCRIPTION

The TEA7089A is a Telephone Analog Front End
device, TAFE, which integrates the three basic
functionsof a standardtelephoneset :

- Speechnetwork,

- DTMF generator,

- Ringer generatoron buzzer.
A complete telephone set can be designed using

TEA7089A associated with a low cost microcon­troller.

June 1998

MIC1

MIC2

GTR

V

GND

IVLS

V

V

V

GREC

5
6
7
8

CC

9
10
11

S

12

L

13

MC

14

24
23
22
21
20
19
18
17
16
15

DATA

MSK
OSC
RI

PON

RES

V

RING

BUZ

EAR+

EAR-

7089A-01.EPS

1/17

TEA7089A

SPEECH

Thespeech network includes :

- a lownoisetransmitchannel suitablefor anykind
of microphonetransducer. Softclippingon trans­mit line signal is provided by the chip.

- a low noise receive channel with symmetrical
outputs to be compatiblewith both piezoceramic
and electrodynamicearpiece. An additional 6dB

RINGER

Up to 8 different tones can be generated by the
TEA7089Aringer.The digitalvolume controlof the
ringer can be performed through a specific com­mand(4 steps).A ringindicationsignal is provided
to the microcontroller by the TEA7089A.If more
tones are requested the input RM/MSK allows to

inject tones generatedby the microcontroller.
gain can be inserted in the receive channel
throughsoftware control.

- a linelengthgain control(AGC)withstartingpoint
ofgainregulationfixedat25mAlinecurrent;slope
of gainregulationis externallyadjustablewithone
resistor.AGCcan beremovedbyhardware(maxi­mumgain flat) or by software(-2dBflat).

The phoneimpedanceand sidetone can be tuned
throughexternal networks.

FURTHERADVANTAGES

The microcontroller power supply is provided by the
TEA7089A.Thepowersupplyisspecif i cal l ydesigned
tocopewitha longflas horalonggroundkeyduration.

The TEA7089A is able to supply the necessary
current to an external speakerphone circuit
TEA7540 and loudspeaker amplifier TEA7532
without any additionalcircuitry.

Line current and reset indications are provided to

DTMF GENERATOR

The onboard DTMF generator fullfils the CEPT
requirementswith an externalsinglepole filter.

the microcontrollerby theTEA7089A.
The microcontroller drivesthe TEA7089Athrough

a 2 wires serial interface.

PIN DESCRIPTION

Name Pin N° Description

SOFT 1 Transmit Softclipping Time Constant

RECIN 2 Receiving Input

SN 3 Sidetone Network Input

AGC 4 Line Current Regulation Stop Value
MIC1 5 Microphone Input
MIC2 6 Microphone Input

GTR 7 Transmit Gain Adjustment

V

CC

GND 9 Ground

IVLS 10 Line Current Source Power Supply

V

S

V

L

V

MC

GREC 14 Receive Gain Adjustment

EAR- 15 Negative Earphone Output

EAR+ 16 Positive Earphone Output

BUZ 17 RingerBuzzer Output

VRING 18 Ring Power Supply

RES 19 Reset

PON 20 Power On

RI 21 Ring Indicator
OSC 22 Oscillator Input
MSK 23 Mask, Ring Melody Input

DATA 24 Data Input

DCL 25 DataClock Input

V

RMC

V

REF

DTMF 28 DTMF Filter

2/17

8 Transmit and Receive Part Power Supply

11 Voltage Stabilizer
12 Positive Line
13 Unregulated Microcontroller Power Supply

26 Microcontroller Stabilized Power Supply
27 Reference Voltage (VCC/2)

7089A-01.TBL

Figure1 : Block Diagram

TEA7089A

CC

V

Sidetone

C30

R13

To Line

To µP

C12

C1

R40 + R15

TEA7089A

RI

21

2

RECIN SN

IVLSV

C15

C16

V

18

SUPPLY

RING POWER

LINE CURRENT

POWER SUPPLY

RMCVRING

26

BUZZER

SUPPLY

LOGIC POWER

BUZ

17

AMPLIFIER

& AGC

SIDETONE

MUTE

AGC

RING

CONTROL

C10

MC

V

13

GENERATOR

SERIAL

REGULATOR

To µP

MSK

DCL

232425

DTMF

GENERATOR

DATA

µP

INTERFACE

REF

V

OSCILLATOR /2

CONTROL

PON & RESET

OSC

1920 22

To µP

PON RES

GND

9

To Line

C8

R10

R11

CC

V

L

R12

12 8 310

S

V

C11

MUTE

DTMFAGC

28

567

MIC1

AGC

MIC2

Microphone

4

R25

CC

V

C3

C3

KVL

SOFT

R4

IN

V

1

GTR

R8

VSTAB

Earphone

Amplifier

EAR-

Earphone

-1

15

REF

V

11

27

REF

V

R14

14

GREC

16

EAR+

R17

C14

7089A-02.EPS

3/17

TEA7089A

ELECTRICALCHARACTERISTICS

Theblock diagram is given in Figure 1.
Thevalues of the differentnetworks used in this datasheetare defined as followed:

- The return loss is adjusted by R10 of 600Ω.

- The transmitadjust gainnetworkR8 is calculatedinorder to havea gainof46dB typicalwith I

- The sidetone networkZST is set to be lower than 20dB (Vear/Vmic)on a 600Ωloadon line.

- The DC characteristicsare setby a resistorof 82kΩ betweenV

and VS.

L

Absolute MaximumRatings

Symbol Parameter Value Unit

I

LINE

I

RING

T

T

oper

stg

T

Authorized Voltage on

Pin 2 - RECIN
Pin 3 - SN
Pin 8 - V
Pin 10 - IVLS
Pin 12 - V
Pin 13 - V
Pin 17 - BUZ
Pin 18 - V
Pin 19 - RES
Pin 20 - PON
Pin 21 - RI
Pin 22 - OSC
Pin 23 - MSK
Pin 24 - DATA
Pin 25 - DCL
Pin 26 - V

CC

L
MC

RING

RMC

V

V
V
V
V
V
V
V

RING

RMC
RMC
RMC
RMC
RMC
RMC
RMC

Line Current 120 mA
Ring Current 50 mA
Operating Temperature -25, +70 °C
Storage Temperature -55, +150 °C
Junction Temperature -25, +150 °C

j

13
12
11

6

12

6

+0.3, GND -0.3

27
+0.3, GND -0.3
+0.3, GND -0.3
+0.3, GND -0.3
+0.3, GND -0.3
+0.3, GND -0.3
+0.3, GND -0.3
+0.3, GND -0.3

5

LS

=22mA.

V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V

7089A-02.TBL

DC Characteristics(T

=25°C; Logic in Default Modeunless otherwise noted)

amb

Symbol Parameter Test Conditions Min. Typ. Max. Unit

V

I

VRMC

V

RMC

I

VMC

I

LS

L

Line Voltage

- In Speech and DTMF Mode

- In Mask Mode
Stabilized Supply Voltage

- Output Current

- Output Voltage IRMC = 1.5mA 3.15 3.35 3.55 V
Unstabilized Supply Voltage

- Start up Current

- Output Current
Line Current Source Supply Test 1,VLS=0V;VMC= 3.6V

Test 1

= 22mA

I

L

= 90mA

I

L

= 22mA

I

L

Test 1, IL= 22mA

V

MC

V

MC

= 22mA

I

L

= 90mA

I

L

= 22mA

L

= 2.5V, I
= 3.6V, I

Test 1, I

VRMC
VRMC

= 1.5mA
= 0mA

4

6.7

4.6

7.5

5.2

8.3
3

1.5 mA

10 15

3

10
67

14
75

18
82

Theline current sourcesupply dependsof IL:

- For I

- For I
Onthis pin the maximumoutput levelis : V

4/17

< 20mA: ILS(mA)= 0.765 x IL(mA)- 1.4mA

L

> 20mA: ILS(mA)= 0.92x IL(mA)- 4.5mA

L

10=V12

- (1.2+ 10 x ILS) and V10<6V

V
V
V

mA
mA

mA
mA

TEA7089A

ELECTRICALSPECIFICATIONS(continued)
AC Characteristics(T

Symbol Parameter Test Conditions Min. Typ. Max. Unit

R1 Return Loss Test 2, I

TransmitCharacteristics

(T

=25°C; RL= 600Ω ; f = 1kHz ; Logicin Default Mode unlessotherwisenoted)

amb

Symbol Parameter Test Conditions Min. Typ. Max. Unit

Gtx

Gtxl

Gtxs
Zmic Microphone Input Impedance between MIC1 & MIC2 32 40 48 kΩ

Ntx Noise Test 3, 2kΩ on microphone inputs,

Mmic Microphone Mute Test 3, V

Dtx

V

Max.

L

Microphone Gain Test3, V

Soft Clipping

- Distortion

- Maximum Level on Line

=25°C;RL= 600Ω ; Logic in Default Mode unless otherwisenoted)

amb

= 22mA

f = 300/3400Hz, V

R8 = 1.3kΩ, R25 = 3.9kΩ

I

Test 3, I

L

= -55dBV

m

= 22mA

I

L

= 90mA

I

L

= 22mA

L

= -55dBV, IL= 22mA 60 dB

m

= 22mA, see Figure 2

L

= -41dBV

V

m

= -34dBV 1.5

V

m

= -10dBV

AC

17 dB

4538464047

42

-76 dBmp

2%

dB
dB

Vp

Figure2 : Softclipping

10

Threshold

Level

1

peak on line (V)

AC

V

0.1

0.1 1 10 100
V

microphon e

peak(mV)

Figure3

10

8

6

4

(Pin 12) (V)

L

V

2

VACpeak

0

0 20 406080100

IL(mA)

-15

-10

-5

-2

VACpeak

The maximum gain Gtl is adjustable between 44
and 56dB with R8 :

Gtxl = 20log



820 ⋅




R10 // R

R8 // 50k

+ R11

L

Ω

TheAGCvariationisprogrammedwithoneresistor
connected on Pin AGC. I

is the line current at

SL

whichthe gain must be decreasedby 6dB.

R25 (Ω) =

I

SL

300

− 5mA

For line current lower than I
The transmit and receive gains have a constant

7089A-03.EPS

value.

(R25 > 2.6kΩ)

or higher than ISL,

LL

If no resistor or a resistor higher than 300kΩis
connected on Pin AGC, the gain is constant and
equal to Gtxl and Grxl.±0.5dB.

AGC can be inhibited also through MCU code
”010100”. In this case Tx and Rx gains are fixed
2dB lower than the maximumgain.

The minimumsaturationvoltageof theTEA7089A
respect to ground is 2.2V. On long line, when the
voltage over TEA7089A is low, the softclipping
function automatically limits the AC dynamic to
avoidto reachthe 2.2Vlimiton TEA7089Arespect

7089A-04.EPS

to ground.





5/17

TEA7089A

ELECTRICALSPECIFICATIONS(continued)
ReceiveCharacteristics (T

Symbol Parameter Test Conditions Min. Typ. Max. Unit

E

G

G

Dr Distortion Test 4, Rear = 300Ω,I

Nr Noise Test 4, I

Vear

(010010)

Zout Output Impedance 20 Ω

Sidetone

ff

Eff = (Vear
Gain in Symmetric Mode

Grx = (Vear

RXl
RXs

+

- Vear-) /Vm

+

- Vear-)/V

Earphone Mute I

=25°C; RL=660Ω ; f = 1kHz)

amb

Test 3, V
R14 = 10kΩ, R17 = 15kΩ

= -55dBV, IL= 22mA,

m

Test 6, VL= -14.5dBV, R14 = 10kΩ,

L

R17 = 15kΩ, R25 = 3.9k

= 22mA

I

L

= 90mA

I

L

Vear = -12dBV
Vear = -8dBV

= 22mA -76 dBmp

L

= 22mA, VL= -14.5dBV 60 dB

L

Ω

= 22mA

L

0.7

-6

1.7

-4

22.5 dB

2.7

-2

2
5

dB
dB

%
%

Automatic Gain Control Inhibition (T

=25°C; RL= 660Ω; f = 1kHz no AGC mode selected)

amb

Symbol Parameter Test Conditions Min. Typ. Max. Unit

Gtp
Grp

Transmit Gain
Receive Gain

Ring Characteristics (T

amb

=25°C)

Test3 &Test4, I
Code : 010100

= -55dBV

V

m

= -14.5dBV

V

L

= 22to 90mA

L

Gtxl -5
Grxl -5

Gtxl -4

Grxl -4

Gtxl -3
Grxl -3dBdB

Symbol Parameter Test Conditions Min. Typ. Max. Unit

Ringing Threshold Voltage Test 5 a/b

V

Thri ON

V

Thri OFF

I

CRing

V

t

RON

V

RING

V

RMC

Internal Consumption in Ring
Mode

Microprocessor Supply Voltage 3.45 3.75 4.05 V
Rise Time I
Internal Zener Voltage 27 V
Buzzer V

bout

Freq = 1312Hz

out

Freq. Code 001111

Figure4 : RingerHysteresisRinger

ON

RI high (see Figure 4)
Rl low (see Figure 4)

V

= 10V 1 1.2 mA

RING

= 10mA 100 ms

RING

15

5

VRING = 27Vzener (see Figure 5)

Level Code (011111)
Level Code (011110)
Level Code (011101)
Level Code (011100)

12

4.4

2.2

13

5.6

2.8

1

1.4

Figure 5 : Ringer OutputWaveform

20

9

13.5

6.7

3.4

1.8

V
V

V

RMS

V

RMS

V

RMS

V

RMS

6/17

Ringer

Status

OFF

V

OFF

Ringer Threshold (V

THRI

V

bout

V

)

V

ON

7089A-05.EPS

7089A-06.EPS