SGS Thomson Microelectronics TDA7403D Datasheet
DEVICE INCLUDES AUDIO PROCESSOR,
STEREODECODER AND NOISEBLANKER
HIGH PERFORMANCE SIGNAL PROCESSOR WITH BASIC FUNCTIONS
AM, FM, MPX AND CASSETTEINPUTS
NO EXTERNAL COMPONENTS REQUIRED
FULLY PROGRAMMABLEVIA I
2
C BUS
LOW DISTORTIONANDNOISE
DESCRIPTION
The TDA7403 is a high performancesignal processor specifically designed for car radio applications focused on the low-end market.
The device includes a complete audioprocessor
and a stereodecoder withnoiseblanker.
Switched-capacitors design technique allows to
obtain all these features without external components or adjustments. Using TDA7403 results is
in a very performant low-cost signal processing
TDA7403
BASIC SIGNAL PROCESSOR
PRELIMINARY DATA
SO20
ORDERING NUMBER: TDA7403D
application
The device is fully programmable by I
terface allowing to customize key device parameters and especiallyfilter characteristics.
The BICMOS process combined with the optimized signal processing assure low noise and
low distortionperformances.
2
C bus in-
BLOCK DIAGRAM
8
AM
MPX
1
INPUT
2
MULTIPLEXER
+
AUTO ZERO
9
80KHz
LP
15
V
S
SUPPLY
GND
14 20
CREF
CASS R
CASS L
FM R
FM L
PILOT
CANCELLATION
PLL
SM
11 17
VOLUME BASSTREBLE
DEMODULATOR
+ STEREOADJUST
+ STEREO BLEND
PIL
DET
SOFT
MUTE
DIGITAL CONTROL
25KHz
LP
NOISE
BLANKER
S&H
PULSE
FORMER
2
I
HIGH
CUT
CONTROL
D
A
10
LEVEL
OUT LR
OUT LF
OUT RR
OUT RF
C BUS
19
16
18
12
13
D98AU918
OUT LR
OUT LF
OUT RR
OUT RF
SCL
SDA
October 1998
1/26
This is preliminary information on a new product now in developmentor undergoing evaluation.Details are subject to change withoutnotice.
TDA7403
ABSOLUTE MAXIMUM RATINGS
Symbol Parameter Value Unit
V
S
amb Operating Ambient Temperature Range -40 to 80 °C
T
stg Operating Storage Temperature Range -55 to 150 °C
T
SUPPLY
Symbol Parameter Test Condition Min. Typ. Max. Unit
S Supply Voltage 7.5 9 10 V
V
S Supply Current V
I
SVRR Ripple Rejection @ 1KHz Audioprocessor (all filters flat) 60 dB
ESD
All pins are protectedagainstESD according to the MIL883 standard.
PIN CONNECTION
Operating Supply Voltage 10.5 V
=9V 253035mA
S
Stereodecoder + Audioprocessor 55 dB
CASS R
CASS L
N.C.
N.C.
N.C.
N.C.
N.C.
AM
MPX SCL
LEVEL SM
2
3
4
5
6
7
8
9
10
D98AU919
20
19
18
17
16
15
14
13
12
11
CREF1
OUT LF
OUT RF
OUT LR
OUT RR
V
S
GND
SDA
THERMAL DATA
Symbol Parameter Value Unit
R
th-j pins
Thermal Resistance Junction-pins Max 85 °C/W
2/26
TDA7403
PIN DESCRIPTION
N. Name Function Type
1 CASSR Cassette Input Right I
2 CASSL Cassette Input Left I
3 n.c. not connected
4 n.c. not connected
5 n.c. not connected
6 n.c. not connected
7 n.c. not connected
8 AM AM Input I
9 MPX FM Input (MPX) I
10 LEVEL Level Input Stereodecoder I
11 SM Soft Mute Drive I
12 SCL I
13 SDA I
14 GND Supply Ground S
15 VS Supply Voltage S
16 OUTRR Right Rear Speaker Output O
17 OUTLR Left Rear Speaker Output O
18 OUTRF Right Front Spaeaker Output O
19 OUTLF Left Front Speaker Output O
20 CREF Reference CapacitorPin S
2
C Clock Line I/O
2
C Data Line I/O
(1) See input configuration tree and databyte specification”configuration”
Pin type legenda:
I = Input
O = Output
I/O = Input/Output
S = Supply
3/26
TDA7403
AUDIO PROCESSORPART
Input Multiplexer
MPX input
Cassettestereoinput
AM mono or stereo input
Internalbeep with 2 frequencies(selectable)
Mixablephone and beep signals
Loudness
Firstor secondorder frequencyresponse
Program mablecenterfrequencyand qualityfactor
15 x 1dB steps
Selectableflat-mode(constantattenuation)
Volume control
1dB attenuator
Max. gain 20dB
Max. attenuation79dB
Soft-stepgain control
Bass Control
2nd orderfrequencyresponse
Center frequencyprogrammablein 4(5)steps
DC gain programmable
7 x 2dBsteps
Treble Control
2nd orderfrequencyresponse
Center frequencyprogrammablein 4 steps
7 x 2dBsteps
Speaker Control
4 independentspeaker controls (1dB steps
controlrange 50dB)
Mute Functions
Direct mute drivenby pin SM
Digitally controlled softmute with 4 program-
mabletime constants
ELECTRICALCHARACTERISTICS (V
S = 9V; Tamb =25°C; RL = 10KΩ;all gains= 0dB; f = 1KHz;
unless otherwise specified).
Symbol Parameter Test Condition Min. Typ. Max. Unit
INPUTSELECTOR
R
in
V
CL
S
IN
IN MIN Min. Input Gain -1 0 1 dB
G
IN MAX Max. Input Gain 14 dB
G
G
STEP
V
DC
Input Resistance all inputs exceptPhone 70 100 130 K
Clipping Level 2.2 2.6 V
Input Separation 80 100 dB
Step Resolution 2 dB
DC Steps AdjacentGain Step 0 mV
to G
G
MIN
MAX
1mV
BEEPCONTROL
VRMS Beep Level 350 mV
f
BMIN
f
BMAX
Lower Beep Frequency 600 Hz
Higher BeepFrequency 1.2 KHz
MIXINGCONTROL
MLEVEL Mixing Level Source 0 dB
Source -6 dB
Source -12 dB
Beep/Phone 0 dB
Ω
RMS
4/26
TDA7403
ELECTRICALCHARACTERISTICS
(continued)
Symbol Parameter Test Condition Min. Typ. Max. Unit
VOLUMECONTROL
GMAX Max Gain 20 dB
MAX Max Attenuation 79 dB
A
A
STEP
E
A
Step Resolution 1 dB
Attenuation Set Error G = -20 to 20dB -1.25 0 1.25 dB
G = -60 to 20dB -4 0 3 dB
E
T
V
DC
Tracking Error 2dB
DC Steps AdjacentAttenuation Steps 0.1 3 mV
From 0dB to G
MIN
0.5 5 mV
LOUDNESSCONTROL
ASTEP Step Resolution 1 dB
MAX Max. Attenuation 15 dB
A
f
CMIN
f
CMAX
Lower Center Frequency 200 Hz
Higher Center Frequency 400 Hz
SOFTMUTE
AMUTE Mute Attenuation 70 100 dB
D Delay Time T1 0.48 ms
T
T2 0.96 ms
T3 40.4 ms
T4 324 ms
1V
V
THlow
V
THhigh
R
PU
V
PU
Low Threshold for SM Pin
(1)
High Threshold for SM Pin 2.5 V
Internal Pull-up Resistor 70 100 130 K
Pull-up Voltage 4.7 V
Ω
SOFTSTEP
TSW Switch Time 10 ms
BASSCONTROL
C
RANGE
A
STEP
C Center Frequency fC1 60 Hz
f
BASS Quality Factor Q1 1
Q
DC
GAIN
1) SM pin is active low (mute condition)
2) See description of Audioprocessor Part - Bass & Treble filtercharacteristicsprogramming
Control Range
14 dB
±
Step Resolution 2 dB
C2 70 Hz
f
C3 80 Hz
f
C4 100
f
2 1.25
Q
Q
3
Q
4
(2)
1.5
2
Bass-Dc-Gain DC = off 0 dB
DC = on 4.4 dB
Hz
5/26
TDA7403
ELECTRICALCHARACTERISTICS
(continued)
Symbol Parameter Test Condition Min. Typ. Max. Unit
TREBLECONTROL
CRANGE Control Range ±14 dB
A
STEP Step Resolution 2 dB
f
C
Center Frequency f
C1
f
C2
f
C3
f
C4
10 KHz
12.5 KHz
15 KHz
17.5 KHz
SPEAKERATTENUATORS
C
RANGE
A
STEP
A
MUTE Output Mute Attenuation 80 90 dB
E
E Attenuation Set Error 2 dB
V
DC
Control Range 50 dB
Step Resolution 1 dB
DC Steps Adjacent Attenuation Steps 0.1 5 mV
AUDIO OUTPUTS
VCLIP Clipping Level d= 0.3% 2.2 2.6 VRMS
RL Output Load Resistance 2 KΩ
C
L
R
OUT
V
DC
Output Load Capacitance 10 nF
Output Impedance 30 120
DC Voltage Level 3.8 V
GENERAL
e
NO
S/N Signal to Noise Ratio all gain = 0dB flat; V
d Distortion V
S
C
E
T
Output Noise BW = 20 Hz to 20 KHz
3
output muted
BW = 20 Hz to 20 KHz
6.5
all gain = 0dB
O =2VRMS 110 dB
bass treble at 12dB; V
2.6V
RMS
=1V
IN
V
=1V
IN
; all stages 0dB 0.002 %
RMS
;Bass&Treble= 12dB 0.05 %
RMS
=
O
100 dB
Channel separation Left/Right 80 100 dB
Total Tracking Error AV= 0 to -20dB 0 1 dB
A
V = -20 to -60dB 0 2 dB
Ω
V
µ
V
µ
6/26
DESCRIPTION OF THE AUDIOPROCESSOR
Figure 1. Input stages
TDA7403
CASSETTE
100K
AM
100K
MPX
100K
STEREODECODER
Input stages
The input circuits are the same as in preceeding
ST audioprocessors with exception of the CD inputs (see figure 1).
The typicalinput impedance is 100kΩ.
AutoZero
In order to reduce the number of pins there is no
AC coupling between the In-Gain and the following stage, so that any offset generated by or before the In-Gain stage would be transferred or
even amplifiedto the output.
To avoid that effect a special offset cancellation
stage called AutoZerois implemented.
To avoid audible clicks the audioprocessor is
muted before the loudness stage during this time.
In some cases, for exampleif the µP is executing
a refresh cycle of the I
2
C bus programming, it is
not useful to start a new AutoZeroactionbecause
no new source is selectedand an undesiredmute
would appear at the outputs. For such applications the TDA7403 could be switched in the ”Auto
Zero Remain” mode (Bit 6 of the subaddress
byte). If this bit is set to high, the DATABYTE 0
could be loaded without invoking the AutoZero
and the old adjustmentvalueremains.
Mixing Stage
This stage offersthe possibility to mix the internal
beep or the phone signal to any other source.
Due to the fact that the mixing stage is also located behind the In-Gain stage fine adjustments
of the mainsource level can be donein thisway.
Loudness
There are four parameters programmable in the
loudnessstage (see fig. 2, 3,4):
IN GAIN
D98AU951
Figure 2. LoudnessAttenuation @ fc = 400Hz
(secondorder)
0.0
-5.0
-10.0
-15.0
-20.0
10.0 100.0 1.0K 10.0K
Figure 3. LoudnessCenterfrequency @ Attn.
= 15dB(secondorder)
0.0
-5.0
-10.0
-15.0
-20.0
10.0 100.0 1.0K 10.0K
- Attenuation
- CenterFrequency
- LoudnessQ
- FlatMode:inthismodethe loudnessstageworks
asa0 -15dBattenuator.
7/26
TDA7403
Figure 4. Loudness@ Attn.= 15dB,fc = 400Hz
(dB)
-5
-10
-15
-20
10 100 1,000 Hz
D98AU844
Softmute
The digitally controlled softmute stage allows
muting/demuting the signal with a I
grammable slope. The mute process can either
be activated by the softmute pin or by the I
2
C bus pro-
2
C
bus. The slope is realized in a special S shaped
curve to mute slow in the critical regions (see figure 5).
2
For timing purposes the Bit 3 of the I
C bus output register is set to 1 from the start of muting until the end of demuting.
Figure 5. Softmute Timing
1
EXT.
MUTE
+SIGNAL
REF
-SIGNAL
1
2
I
C
BUS
OUT
D97AU634
Note: Please notice that a started Mute action is always terminated
and could not be interruptedby a change ofthemute signal.
Time
Figure 6. Soft Step Timing
VOUT
2dB
1dB
Softstep Volume
When volume level is changed often an audible
click appears at the output. The root cause of
those clicks could be either a DC offset before
the volume stage or the sudden change of the
envelope of the audio signal. With the Softstep
feature both kinds of clicks could be reduced to a
minimum and are no more audible (see figure 6).
Bass
There are three parameters programmable in the
bass stage(see figs 7, 8, 9, 10):
- Attenuation
- Center Frequency (60, 70, 80 and 100Hz)
- QualityFactors(1, 1.25, 1.5 and 2)
DC Mode
In this mode the DC gain is increased by 4.4dB.
In addition the programmed center frequencyand
quality factor is decreased by 25% which can be
used to reach alternative center frequencies or
quality factors.
10ms
-1dB
-2dB
Note: For steps more than 1dB the softstep mode should be
deactivated because it could generate a 1dB error during the
blend-time
Time
D97AU635
Treble
There are two parameters programmable in the
treble stage (see figs 11, 12):
- Attenuation
- CenterFrequency(10, 12.5, 15 and 17.5kHz).
Speaker Attenuator
Due to practical aspects the steps in the speaker
attenuators are not linear over the full range. At
attenuations more than 24dB the steps increase
from 1.5dB to 10dB (please see data byte specification).
8/26
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