SGS Thomson Microelectronics TEA7092 Datasheet

TEA7092

TELEPHONE ANALOG FRONTEND

SPEECH

.

DC LINE CURREN T RANGE FROM 6 TO120mA

.

EXTERNALLYADJUSTABLE:

- Tx ANDRxGAIN

- MAXIMUMTRANSMIT LEVEL

- RETURN LOSS

- SIDETONENETWORKS

- Tx ANDRxAGC(LINECURRENT STARTUP
VALUE ANDSLOPE)

.

SOFTCLIPPINGONTxCHANNEL

.

SQUELCH ON Tx CHANN ELT O REDUCE NOISE
ENVIRONMENT AND TO IMPROVE HOWLING
IMMUNITYIN LOUDHEARIN GMODE

.

RECEIVING AMPLIFIER FOR PIEZO AND
ELECTRODYNAMICTRANSDUCERS

.

FREQUENCY GENERATOR FOR WAITING
MELODY

.

ERRORBEEP GENERATOR

.

HOLD LINE CURRENT DETECTOR FOR
TRANSFER/AUTORELEASEFEATURE

.

PROGRAMMABLE BY MICROCONTROLLER
SERIALBUS:

- -6dBON Tx CHANNEL

- +6dBONRx CHANNEL

- AGCINHIBITION ONTx ANDRxCHANNELS
FORPABX USE

- SQUELCHINHIBITION

GROUPLISTENING / ONHOOK DIALING

.

ANTI-HOWLING WITH ACOUSTIC FEED­BACKSYSTEMCOUPLEDTOSQUELCH

.

RING MELODY CONTROL AND ERROR
BEEPGENERATORS

.

PROGRAMMABLE BY MICROCONTROLLER
SERIALBUS:

- DIGITALVOLUME CONTROL (7 STEPS OF
4dB EACH) AND OFF MODE

.

PROGRAMMABLE BY MICROCONTROLLER
SERIALBUS:

- DIGITALVOLUME CONTROL(15STEPSOF
4dB EACH) AND OFF MODE

- RING FREQUENCY GENERATOR (MORE
THAN200 FREQUENCIES AVAILABLE)

DIALING

.

PROGRAMMABLE BY MICROCONTROLLER
SERIALBUS:

- DTMF GENERATOR

- 2V DC LINE VOLTAGE DURING THE MAKE
PERIODIN PULSEMODE

MICROCONTROLLER INTERFACE

.

3.5V STABILIZEDSUPPLY

.

TWO WIRESSERIAL BUS INTERFACE

.

RINGINDICATOR

.

PON LINE CURRENTINDICATOR

.

RESETSIGNAL

.

LINE CURRENT VARIATION INDICATOR
(FOR TRANSFERFEATURE)

.

OSCILLATORWITH STANDBY MODE

CORDLESS AND ANSWERING MACHINE
INTERFACE

.

SELF BIASED LOUDSPEAKER AMPLIFIER
AND MICROCONTROLLER INTERFACE FOR
ANSWERING MACHINE

.

SIGNAL INPUT AND OUTPUT INTERFACE
FOR CORDLESS

.

V

SUPPLYCANBE EXTERNALLYFORCED

RMC

TO 5V FOR EASY INTERFACE WITH A MAIN
POWEREDMICROCONTROLLER

HANDFREE INTERFACE

.

PINS AND SOFTWARE FACILITY FOR EASY
INTERCONNECTION WITH HANDSFREE
CONTROLLER I.C. LIKE TEA7540

RING ON LOUDSPEAKER

.

EMBEDDED SWITCH MODE POWER SUP­PLY DRIVER TO FEED THE LOUDSPEAKER
AMPLIFIERDURINGRING MODE

July 1996

TQFP44

(Plastic Quad Flat Package)

ORDER CODES : TEA7092TQ - TEA7092TQT

1/24

TEA7092

DESCRIPTION

The TEA7092is a TelephonesetAnalogFrontEnd
(TAFE) interface intended for use in conjunction
with amicrocontroller.
In thisconfigurationthe TEA7092providesaworld­wide telephone set with loudhearing and melody
ringer onloudspeaker.An handsfreetelephoneset
can be built by adding the TEA7540 handsfree
controller.
The simpleinterfacewitha+5Vmainsupplyallows
to use the TEA7092 in terminal like Answering
machine,FAX and cordlessbase station.
Repertory dialer (memory on MCU) and various
features (HOLD, Tone/Pulse,Flash, Mute, adjust­able Ringer and Loudspeaker levels...) are pro­grammable by the MCU through the serial bus
interface.

PIN CONNECTIONS

DTMF2

GNDP

RCO

V

V

VL

V

REFL

LSIN

LSSOF
DTMF1

V

RMC

OSC
RI/VI

RESET

LSOUT

4443424140393837363534

1

LS

2

MC

3
4
5
6
7
8
9
10
11

1213141516171819202122

The MCU throughthe serial bus interface.
The concept using TAFE and Microcontroller is

calledBICHIPapproach.

BENEFITS

The benefits of this concept are :

- Saving of externalcomponents.

- Easy upgrade of the features (memories, LCD
driver,Answeringmachine, FAX, Cordless ...).

- Replacement of configuration switches
(PABX/Public, Tone/Pulse) and potentiometers
for loudspeakerand ringer control, by EEPROM
settings.

- Reliability and cost improvements.

RSU

SWP

VZP

GREC

EAR-

EAR+

ISL

33
32
31
30
29
28
27
26
25
24
23

ILL
AGND
SLP
VS
I

REF

SOFTL
TSOFT
V

CC

V

REF

MIC2
MIC1

2/24

PON

CLK

DATA

SNSL

SNLL

ASQ

ASC

RECIN

REOUT

GTR

HFIN

7092-01.EPS

PIN DESCRIPTION

Pin Number Name Description

1V
2V

LS

MC

3 VL Transmit Output
4V

REFL

5 LSIN Loudspeaker Amplifier Input
6 LSSOF Loudspeaker Softclipping Time Constant
7 DTMF1 DTMF Filter 1
8V

RMC

9 OSC Oscillator Input
10 RI/VI Ring Indicator / Line Current Variation Indicator
11 RESET Microcontroller Reset Output
12 PON Line Current Indicator Output
13 CLK Serial Bus Clock Input
14 DATA Serial Bus Data Input
15 SNSL Short Line Sidetone Network Input
16 SNLL Long Line Sidetone Network Input
17 ASQ Antiacoustic & Squelch Time Constant
18 ASC DC Offset Cancellation of Squelch Amplifier
19 RECIN Receive Input
20 REOUT Receive Outputfor Handsfree Interface & Loudspeaker Input
21 GTR Transmit Gain Adjustment
22 HFIN Handsfree Microphone Input Referenced to V
23 MIC1 Microphone Input 1 Referenced to V
24 MIC2 Microphone Input 2 Referenced to V
25 V
26 V

REF

CC

27 TSOFT Transmit Softclipping Time Constant
28 SOFTL Softclipping Adjustment
29 I

REF

30 VS Active Self Inductor & DC Characteristic Adjustment
31 SLP DC Mask Slope Adjustment
32 AGND Analog Ground & Negative Line Voltage
33 ILL Long Line Speech Control Adjustment (GMAX)
34 ISL Short Line Speech Control Adjustment (GMAX-6dB)
35 EAR+ Earphone Output
36 EAR- Earphone Output
37 GREC Receive GainAdjustment
38 VZP Switch Mode Power Supply Internal Zener
39 SWP Switch Mode Power Supply Output Switch
40 RSU Ring Start-up Level
41 RCO Ring Power Output Control
42 DTMF2 DTMF Filter 2
43 GND Power Ground & Negative Line Voltage
44 LSOUT Loudspeaker Output

Loudspeaker Power Supply
Unregulated Input of Microcontroller Power Supply

Loudspeaker Reference Voltage (VLS/2)

Stabilized Microcontroller Power Supply

REF
REF

Speech Reference Voltage (VCC/2)
Speech Power Supply

Resistor to Set Reference Current

TEA7092

REF

7092-01.TBL

3/24

TEA7092

BLOCK DIAGRAM

REFL

GND 0V

V

LSSOF

LS

V

LS

V

CC

V

TEA7092

13 4615 161926 30

VLS/2

CTRL

LOGIC

HOLD

ILdc 82.ILac I(vls)

STATUS

I LINE SENSING

ILdc

&OUT TX

LOUDSPEAKER

CURRENT SUPPLY

ILac+dc

DC BIAS

AGC

Gmax-Gtl

A
100

INPUTS

LSOUT

SAT

DETECT

DIGITAL

MUX

44

VOLUME

CONTROL

7 steps 4dB

AGC

+RING

LOUDSPEAKER

GND 0V

POWER

LOUDHEARING

Gtl -10 -15 -20 -25dB

VLS

VZP

38

POWER

RCO

41

RING SIGNAL

OUTPUT POWER

(3mA)

CURRENT

EXTRACTOR

GND 0V

RSU

40

POWER

SWITCH MODE

RING

OPTIMISATION

RING

INDICATOR

DC

SERIAL

REGULATOR

ILdc ILac+dc

SWP

39

SUPPLY

CONTROL

ILdc

PON &

GND 0V

RESET

CONTROL

OSCILLATOR

LOGIC CONTROL

RING

MELODY

GENERATOR

LOGIC

SERIAL INTERFACE

MICROCONTROLLER

MUTE

LS

V

GND 0V

3.58MHz

9

14 13 10111282

RMC

V

PON RESET DATA CLK RI/VI OSC

RMC

V

MC

V

4/24

Zasl

LINE

Zall

VS RECINVL SNSL SNLL

CC

V

ILdc

VCC/2

25

REFIREF

V

ILdc

DC

CARACTERISTIC

I&V

REFERENCES

29

31

SLP

LSIN

5

MIXER

SIDETONE

AGC

20

37

GREC

REOUT

AGC CONTROL

MUTE

VERSUS

LINECURRENT

VREF

36

EAR-

RX & TX

-1

EARPHONE

AMPLIFIER

35

EAR+

EARPHO NE

17

ASQ

ASC

dc cut

VL

18

SOFTL

Tx. AMP

MUTE & DTMF

G=200

SQUELCH

ANTI-HOWLING

SOFTCLIPPING

272824

MIC2

TSOFT

1/RGT

AGC

A=10

23

MIC1

MICRO

HAND-FREE

22

HFIN

C21

21

GTR

333432

ILL

RGT

BEEP

VREF

DTMF

I-DACLF I-DACHF

ISL

AGND

SINE CODE

43

GND

742

DTMF1 DTMF2

GND 0V

7092-02.EPS

TEA7092

ABSOLUTEMAXIMUM RATINGS

Symbol Parameter Value Unit

V

RECIN

V

L

I

L

V

RSU

V

SWP

V

VLS

V

VCC

V

VM

V

VRMC

V

PON

V

CLOCK

V

DATA

V

RI/VI

T

oper

T

T

stg

Note: Typical Thermal resistance TQFP44 Copper lead frame70° K/W @ 1W.

Supply Voltage 13 V
Line Voltage 13 V
Line Current 0.15 A
Ring InputVoltage 22 V
Output SwitchVoltage 7 V
Loudspeaker Part Supply 5.5 V
Speech PartSupply Voltage 10 V
Unregulated Microprocessor Supply Voltage 5.5 V
Regulated Microprocessor Supply Voltage 5.5 V
Power-On Out Voltage V
Clock In Voltage V
Data In Voltage V
RI/VI Out Voltage V

+0.3V, GND-0.3V V

RMC

+0.3V, GND-0.3V V

RMC

+0.3V, GND-0.3V V

RMC

+0.3V, GND-0.3V V

RMC

Operating Temperature -20, +70 °C
Junction Temperature -20, +150 °C

j

Storage Temperature -55, +150 °C

7092-02.TBL

Figure 1 : SafeArea

140
120
100

80

(mA)

L

60

I

40
20

0

02468101214

VL(V)

7092-03.EPS

5/24

TEA7092

DC CHARACTERISTICS (T

BetweenI

) =RS x (40E-6+0.5E-3xIL) +RSLP/55 x (IL- 5.6E-3).

V

L(IL

=8mA and IL= 20mAthe DC slopeis fixed by RS and RSLP :

L

For linecurrenthigherthan20mAthe slopeis fixed by RSLP: V

=25°C,see Test 1)

amb

)=VL(20E-3)+ RSLP/55x(IL- 20E-3).

L(IL

Symbol Parameter Test Conditions Min. Typ. Max. Unit

4.1

4.7

V

V

I

LSQ

Line Voltagein Speech Mode IL= 20mA

L1

Line Voltageafter Having Sent

L2

0010101 Mask Code
Loudspeaker Amplifier Quiescent

Bias Current

Unstabilized Supply :
I(VMC)1
I(V

MC

V

RMC

(V

L-VLS

(V

L-VLS

I

LS1

- Startup Current

)2

- UnregulatedInput Current

Stabilized Microprocessor Supply IL= 20mA, I(V

DropVoltage V

I

LS

)1
)2

Loudspeaker CurrentSupply VLS=2V

RETURN LOSS (T

=25°C,see Test 2

amb

= 90mA

I

L

6.6

IL= 20mA 1.6 2.5 V

VLS= 4.5V 1.1 2.2 mA

= 20 mA, VLSno connect, VMC= 2.4V

I

L

V

RMC

V

RMC

LAC

IL= 20mA
I

L

I

L

I

L

= 2.4V
= 3.75V

=0V

RMS

= 90mA

= 20mA
= 90mA

) = -1.8or 0mA 3.2 3.5 3.75 V

RMC

10215

117013

5.25

7.5

8.4VV

2.7 3.6mAmA

1.1

1.3

1.8

2.3VV

77

Symbol Parameter Test Conditions Min. Typ. Max. Unit

RLoss Return Loss I

= 20mA, f = 1000Hz 20 23 dB

L

mA
mA

7092-03.TBL

7092-04.TBL

TRANSMIT CHARACTERISTICS

The maximum gain Gtl is adjustable between 44
and 56dB versusRGT value

Gtl = 20 x log





= internal impedance at Pin VL#8kΩ.

Z

IN

( RZ// RL + R3 ) // Z

820 x

RGT// 50kΩ



IN




The AGC variation is programmable through two
external resistorsconnected on Pins ILL and ISL.
ILL is the line current at which the gain is at the
maximumvalue and ISLis the line currentat which
the gain is at the maximum value minus 6dB. For
line current lower than ILL or higher than ISL, the
transmitand receivegains have a constantvalue.
The following formulas give RLL and RSL values
versus ILL and ISL.

RSL =

310

ISL− 5.6mA

and RLL =

310

ILL − 5.6mA

Tx Softclipping(see Figure 2)
Figure2 : TxSoftclipping and Distortion

at I

=20mA

L

2

V

LINE

Distortion

1

)

0.5

RMS

(V

L

V

0.2

0.1

0.05

0.2 0.5 1 2 5 10 20 100
(mV

V

MIC1-MIC2

RMS

)

50

12

10
8

6

4
2
0

) (%)

L

D(V

7092-04.EPS

6/24

TEA7092

TRANSMIT CHARACTERISTICS (continued)
Maximum Level on Line in Tx (see Figure 3)

The minimumoperating voltage of the TEA7092is 2.5V. At low line currentvalue, when the voltageover
the TEA7092is low, thesoftclippingfunctionautomaticallylimitsthe AC dynamicto avoidto reach the 2.5V
limit on the TEA7092.

When the DCvoltageover the TEA7092is high enough, the AC dynamicis limitedat a valuefixed by the
external resistor RSOFTconnectedon PinSOFTL.
The Valueof RSOFT is performed by : RSOFT= (RS x 50E

-6

- 0.8- VacPeak)/ 40E

-6

Tx Characteristics (T

=25°C,f = 1kHz,seeTest 3)

amb

Symbol Parameter Test Conditions Min. Typ. Max. Unit

Gtl

Transmit gain in Handset Mode V

Gtsm

Transmit gain in Handsfree Mode V

Ghl

Ghfm

Gt-6dB Transmit Gain

(-6dB intransmit path)

Zmic

Zhf

Ntx
Nhf

Handset Mic Input Impedance
Handsfree MicInput Impedance

Transmit Noise in Handset Mode
Transmit Noise in Handsfree Mode

Mmic Microphone Mute V

V

Lpeak

Transmit SoftclippingLevel See Figure 2, Vem= -42dBV, IL= 20mA 1.0 1.4 1.8 Vpeak

Transmit Distortion I
Dtx1
Dtx2

Squelch on Transmit Channel (T

amb

=25°C,f = 1kHz, IL=20mA, seeTest3)

= -48dBV

em

= 20mA

I

L

= 90mA

I

L

= -28dBV, Code 0110010

hfin

= 20mA

I

L

= 90mA

I

L

= -48dBV, IL= 20mA

V

em

Code 0110110
Between Pins MIC1, MIC2

Between HFIN and V

= 20mA, Code 0110010

I

L

2kΩ between MIC1 & MIC2
2kΩ between HFIN & V

= -48dBV, IL= 20mA 60 dB

em

= 20mA, see Figure 2

L

= -48dBV

V

em

= -36dBV

V

em

REF

REF

443745394641dB

241725192621dB

567dB

301540205025kΩ

-75

-75

dB

dB

kΩ

dBmp
dBmp

1

%

5

%

The principle of the squelch is to reduce the transmitgain as soon as the amplitude of the signal on the
microphoneis lower than a fixed thresholdvoltage, VT2.

Symbol Parameter Test Conditions Min. Typ. Max. Unit

Gtlmax

Gtlmax-Gsq

Transmit Gain V

em1

V

em2

= -75dBV
= -65dBV

36
45

Gsq Gain Variation See Figure 4 / 9 dB

dB
dB

Figure 3 : Line PeakVoltage versus DC Line

Current

10

V

AC Pe a k

(V)

L

V

8

6

4

2

2.5V Min. Line Pea k Voltage

V

20 40 60 80 1000

DC Mask

AC Peak

IL(mA)

Figure4 : TransmitGain versus Microphone

AC Input Signal

Trans mit
Gain (dB)

Gtlmax

Gtlmax - Gsq

7092-05.EPS

V

em1

Dgt

V

T1

V

T2

Microphone AC Voltage

V

em2

Gst

V

(dBV)

7/24

em

7092-06.EPS

TEA7092

RECEIVECHARACTERISTICS (T

=25°C,f = 1kHz)

amb

Symbol Parameter Test Conditions Min. Typ. Max. Unit

Eff Sidetone Efficiency Test 3, V

Gain

Test 2

Grl

Grs

Grs+6

+6dB Code [0010110]

Distortion Test 2, I
Drx1
Drx2

Nrx Noise Test 2, I

Mrx Mute Test 2, I

Z

Z

OUT

Input Impedance Between Pins SNSL & SNLL 120 150 kΩ

IN

Output Impedance 5 Ω

I
I
I

V
V

= -48dBV, IL= 20mA 26 dB

em

= 20mA

L

= 90mA

L

= 90mA

L

= 20mA

L

= -3dBV

ear

= 0dBV

ear

= 20mA -76 dBmp

L

= 20mA, VL= -9dBV 60 dB

L

5

-1.2
5

6

0.8
6

7

2.8
7

3
5

dB
dB
dB

%
%

The sidetoneof theTEA7092usestwo networks,these twonetworksareinternallymixedbetweenlongline
lengthand short line length.

The following equation givesthe sidetone impedanceversus linecurrent: ZAL = K x ZALL+ (1 - K)x ZASL
K=1forI

=ILL ;K= 0 forIL=ISL,and K varieslinear l ybetween1 and0 when ILvari esbetweenILL and ISL.

L

It is possibleto use only the standardone sidetone conceptby short-circuitedPins SNSL ans SNLL.

Gain Control Inhibition FacilityFor PABXApplication

(T

=25°C,IL=20mA, f = 1kHz / NoAGC mode selected 0010100)

amb

Symbol Parameter Test Conditions Min. Typ. Max. Unit

Gtp Transmit Gain Test 2 Gtl - 3 Gtl- 2 Gtl -1 dB
Grp Receive Gain Test 3 Grl- 3 Grl - 1.4 Grl - 0.5 dB

LOUDSPEAKERAMPLIFIER PART
LoudspeakerAmplifier Channel (T

=25°C,f = 1kHz, RLS=50Ω, Vem=0)

amb

The Loudspeakeramplifier channelhas a maximumgain of 35dBbetween Pin LSIN and Pin LSOUT. This
gain is programmablethrough the serialbus interface, 7 stepsof 4dB each.
To avoid distortion, the output level on the loudspeaker is controlled by a softclippingfunction, the time
constant of thisfeature is connectedto LSSOF pin.

Symbol Parameter Test Conditions Min. Typ. Max. Unit

GAIN VHP/Vac Test 4 IL = 20mA
GLS0 GMAX Code: (0 1 0 0 1 1 1) 33.5 35 36.5 dB
GLS1 GMAX-4dB Code: (01 0 0 1 1 0) 29.5 31 32.5 dB
GLS2 GMAX-8dB Code: (01 0 0 1 0 1) 25.5 27 28.5 dB
GLS3 GMAX-12dB Code: (01 0 0 1 0 0) 21.5 23 24.5 dB
GLS4 GMAX-16dB Code: (01 0 0 0 1 1) 17.5 19 20.5 dB
GLS5 GMAX-20db Code: (0 1 0 0 0 1 0) 13.5 15 16.5 dB
GLS6 GMAX-24dB Code: (01 0 0 0 0 1) 9.5 11 12.5 dB
GLS7 GMAX-28dB Code: (01 0 0 0 0 0) 5.5 7 8.5 dB

Mls Mute Loudspeaker Test 4 -30 dB
lsin Input Impedance 30 40 50 kΩ

PLS1
PLS2

Output Power Test 4, Gain= GLS0, V

IL= 20mA, D ≤ 2%

= 90mA, D ≤ 2%

I

L

= 0.15V

IN

RMS

13
40

18
55

mW
mW

8/24