APPLICATION NOTE
TEA7092 - TELEPHONE SET INTEGRATED CIRCUIT
AN848/1096
CONTENTS
Pages
I.
TEA7092 GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3
I.1.
SETTING THE TEA7092 APPLICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3
I.2.
PINOUT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4
I.3.
BLOCK DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5
I.4.
INPUT/OUPUT CONFIGURATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6
II.
SPEECH FEATURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14
II.1.
DC CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14
II.1.1.
TEA7092 DC Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14
II.1.2.
Telephone Set DC Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14
II.1.3.
Start Up Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15
II.1.4.
Further Information (V
CC
/V
REF
/I
REF
/V
MC
/V
RMC
/V
LS/
V
REFL
) . . . . . . . . . . . . . . . . . . . . . . .
17
II.2.
IMPEDANCE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
18
II.3.
TRANSMIT CHANNEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
19
II.3.1.
General Information - Maximum Gain Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
19
II.3.2.
Softclipping Threshold (Maximum Line Level). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
20
II.3.3.
Line Loss Compensation A.G.C. Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
21
II.3.4.
A.G.C. Inhibition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
21
II.3.5.
Transmit Squelch / Antiacoustic Feedback Stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
22
II.4.
SIDETONE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
23
II.4.1.
General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
23
II.4.2.
One Sidetone Network Principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
24
II.4.3.
Line Tracking Sidetone Network Principle. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
24
II.4.4.
Sidetone Programming for PABX Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
25
II.5.
RECEIVE CHANNEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
26
II.5.1.
General Information - Maximum Gain Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
26
II.5.2.
Maximum Output Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
27
II.5.3.
Line Loss Compensation / A.G.C. Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
30
II.5.4.
A.G.C. Inhibition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
30
II.5.5.
+6dB Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
30
II.6.
HANDSFREE INTERFACE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
30
III.
CALL PROGRESS MONITOR AND GROUP LISTENING MODES . . . . . . . . . . . . . . .
31
III.1.
GENERAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
31
III.2.
LOUDSPEAKING PART SUPPLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
32
III.3.
SOFTCLIPPING STAGE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
33
III.4.
ANTIACOUSTIC FEEDBACK FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
33
III.5.
MAXIMUM OUTPUT POWER. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
35
III.6.
EXTERNAL POWER SUPPLY FACILITY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
36
III.7.
RING MELODY CONTROL MODE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
37
III.8.
BEEP ERROR GENERATOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
38
1/57
CONTENTS (continued)
Pages
IV.
MICROCONTROLLER INTERFACE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
39
IV.1.
MICROCONTROLLER POWER SUPPLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
39
IV.2.
RESET AND PON SIGNALS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
39
IV.3.
SERIAL BUS INTERFACE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
41
IV.3.1.
Different Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
41
IV.3.2.
Software Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
45
IV.3.3.
Serial Bus Codes Actions on Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
46
IV.4.
RING INDICATOR / LINE CURRENT VARIATION INDICATOR . . . . . . . . . . . . . . . . . .
47
IV.5.
OSCILLATOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
47
IV.6.
MICROCONTROLLER SIGNAL CONTROL IN THE DIFFERENT MODES. . . . . . . . . .
47
V.
DIALER FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
48
V.1.
DTMF DIALER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
48
V.2.
SINE WAVE GENERATOR. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
49
V.3.
PULSE DIALER INTERFACE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
49
VI.
RINGER FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
50
VI.1.
RINGER POWER SUPPLY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
50
VI.2.
START UP THRESHOLD LEVEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
50
VI.3.
RING FREQUENCY GENERATOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
51
VI.4.
OUTPUT POWER OPTIMIZATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
51
VI.4.1.
Switch Mode Power Supply Concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
51
VI.4.2.
Switch Mode Power Supply Losses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
52
VI.4.3.
Output Power Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
53
VI.5.
MICROCONTROLLER MANAGEMENT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
54
VI.6.
RING SOFTWARE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
55
VII.
APPLICATION DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
56
TEA7092 - TELEPHONE SET INTEGRATED CIRCUIT
2/57
I - TEA7092 GENERAL INFORMATION
I.1 - Setting the TEA7092 Application
TEA7092 is a telephone set integrated circuit de-
signed to meet various country's requirements.
TEA7092 is adapted to each country through ex-
ternal component value modifications.
TEA7092 performs the following features :
- Speech (Line interface & 2 wires / 4 wires)
- Call progress monitor (Exchange tone heard in
the loudpeaker & On-Hook dialing)
- Group listening (Handset & loudspeaker used
simultaneously)
- Handfree interface
- Ring on Loudspeaker
- DTMF dialing
- DC mask in Pulse dialing mode (Tip & Ring
voltage reduced during make period)
- Microcontroller interface
- Line current variation detector for transfer
- Waiting melody generator
- Beep error generator
All these features can be programmed by the as-
sociated microcontroller through the serial bus in-
terface.
Make a copy of the last page of this document
and keep it as a reference, when you read this
application note, if you want to refer to the
external component names.
When setting the application, it is preferable to
respect the following flow chart :
Speech Part and DTMF Dialing
- Start your application with the default component
values given at the last page of this document
(typical application).
- Adjust the DC and START-UP characteristics.
- Adjust the Impedance (return loss).
- Adjust the Transmit parameters (softclipping
level, gain, frequency response curve).
- Adjust the Sidetone network(s)*.
- Adjust the Receive parameters (gain, frequency
response curve)*.
- Adjust the DTMF output level.
* Each of these two adjustments is influenced by the other one, for
more information, see Sections II.4 & II.5.
Call Progress Monitor and Group Listening
- Adjust the Loudspeaking amplifier (gain, fre-
quency response curve) without handsetconnec-
tion in order to avoid influence of the handset
microphone.
- Adjust the Antiacoustic feedback efficiency.
Ringer Part
- Choose the Ring frequency melody.
- Adjust the Ring start up level.
- Optimize the loudspeaker output power.
Further Features
- Tip & Ring DC value in the make period in pulse
dialing mode,
- Line current variation detector for transfer,
- Waiting melody generator,
- Beep error generator,
- Microcontroller interface,
are essentialy software programming.
Note : Throughout the application note, I
L
is the
current which power supplies the complete appli-
cation (current is equivalent to the one delivered by
an exchange to power a telephone set). For the
entire application note, unless otherwise specified,
the component values are those given at the last
page of this document (typical application).
TEA7092 - TELEPHONE SET INTEGRATED CIRCUIT
3/57
I.2 - Pinout
Pin N
Name
Function
1
V
LS
Loudspeaker Power Supply
2
V
MC
Unregulated Microcontroller Power Supply
3
V
L
Transmit Output Stage
4
V
REFL
Loudspeaker Reference Voltage (V
LS
/2)
5
LSIN
Loudspeaker Amplifier Input
6
LSSOF
Loudspeaker Softclipping Time Constant
7
DTMF1
DTMF Filter 1
8
V
RMC
Stabilized Microcontroller Power Supply
9
OSC
Oscillator Input
10
RI/VI
Ring Indicator/Line Current Variation Indicator Output (*)
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
16
SNLL
Long Line Sidetone Network
17
ASQ
Anti-Acoustic Feedback and Squelch Time Constant
18
ASC
DC Offset Anti-Acoustic Feedback and Squelch Amplifier Suppression
19
RECIN
Receive Input and Positive Line Voltage
20
REOUT
Receive Output for Handfree Interface and Loudspeaker Input
21
GTR
Transmit Gain Adjustment
22
HFIN
Handfree Microphone Input Referenced to V
REF
23
MIC1
Microphone Input 1 Referenced to V
REF
24
MIC2
Microphone Input 2 Referenced to V
REF
25
V
REF
Speech Reference Voltage (V
CC
/2)
26
V
CC
Speech Power Supply
27
TSOFT
Transmit Softclipping Time Constant
28
SOFTL
Transmit Softclipping Level Adjustment
29
I
REF
Resistor to Set Reference Current
30
V
S
Active Inductor and DC Characteristic Adjustment
31
SLPE
DC Mask Slope Adjustment
32
AGND
Analog Ground and Negative Line Voltage
33
I
LL
Long Line Speech Control Gain Adjustment (GMAX)
34
I
SL
Short Line Speech Control Gain Adjustment (GMAX - 6dB)
35
EAR+
Positive Earphone Output
36
EAR-
Negative Earphone Output
37
GREC
Receive Gain Adjustment
38
V
ZP
Switch Mode Power Supply Internal Zener
39
SWP
Switch Mode Power Supply Output
40
RSU
Ring Start Up Level
41
RCO
Ring Power Output Control
42
DTMF2
DTMF Filter 2
43
GND
Power Ground and Negative Line Voltage
44
LSOUT
Loudspeaker Output
* Logic Interface.
I - TEA7092 GENERAL INFORMATION (continued)
TEA7092 - TELEPHONE SET INTEGRATED CIRCUIT
4/57
29
1
3
4
6
15
16
19
26
30
DC
CARACTERISTIC
I&
V
REFERENCES
25
31
5
20
37
ILdc
ILdc
SIDETONE
MIXER
AGC
V
REF
MUTE
EARPHONE
-1
AMPLIFIER
36
35
AGC
CONTROL
VERSUS
LINE
CURRENT
27
28
24
23
A=10
22
HAND-FREE
SQUELCH
ANTI-HOWLING
G=200
17
18
dc
cut
MUTE
&
DTMF
1/RGT
21
33
34
32
43
I-DAC
LF
I-DAC
HF
SIDE
CODE
V
REF
BEEF
74
2
LOUDSPEAKER
CURRENT
SUPPLY
&
OUT
TX
ILdc
82.ILac
I(vls)
ILac+dc
ILdc
ILa c+dc
RX
&
T
X
DTMF
HOLD
I
LINE
SENSING
STATUS
ILdc
LOGIC
CTRL
V
LS
/2
AGC
DIGITAL
VOLUME
CONTROL
7
steps
4dB
MUX
Gtl
-10
-15
-20
-25dB
POWER
AGC
INPUTS
DC
BIAS
SAT
DETECT
200
A
LOUDHEARING
44
POWER
CURRENT
EXTRACTOR
(3mA)
SERIAL
DC
REGULATOR
PON
&
RESET
CONTROL
LOGIC
MICROCONTROLLER
SERIAL
INTERFACE
14
13
10
11
12
8
2
MUTE
ILdc
9
LOGIC
CONTROL
OUTPUT
POWER
RING
SIGNAL
OPTIMISATION
RING
INDICATOR
CONTROL
SWITCH
MODE
POWER
SUPPLY
RING
39
40
41
38
V
LS
Gmax-Gtl
TEA7092
V
REF
I
REF
SLPE
LSIN
REOUT
GREC
EAR-
EAR+
EARPHONE
ASQ
ASC
SOFTL
TSOFT
MIC2
MIC1
MICRO
HFIN
GTR
C21
RGT
ILL
ISL
AGND
GND
DTMF1
DTMF2
GND
0V
V
MC
V
RMC
V
RMC
PON
RESETN
DATA
CLK
RI/VI
OSC
3.58MHz
V
CC
LINE
V
S
RECIN
V
L
SNSL
SNLL
V
CC
Zall
Zasl
V
LS
V
LS
V
REFL
LSSOF
GND
0V
GND
0V
LSOUT
LOUDSPEAKER
V
ZP
RCO
GND
0V
RSU
+RING
SWP
GND
0V
GND
0V
V
LS
V
CC
/2
RING
MELODY
GENERATOR
OSCILLATOR
Tx
AMP
SOFTCLIPPING
V
L
AGC
AN848-01.EPS
I - TEA7092 GENERAL INFORMATION (continued)
I.3 - Block Diagram
TEA7092 - TELEPHONE SET INTEGRATED CIRCUIT
5/57
PDF 
ZIP