TDA8190 Datasheet, PDF (7/11 Pages) STMicroelectronics – TV SOUND CHANNEL WITH DC CONTROLS

TDA8190
Figure 13 : Power Dissipation versus Supply
Voltage (sine wave operation)
P _tot (W)
4
d = 10%
3
2
RL = 8Ω
1
RL = 16Ω
Vs (V)
0
8 10 12 14 16 18 20 22 24 26 28
Figure 15 : Quiescent Drain and Quiescent Out-
put Voltage versus Supply Voltage
Vo
20
Vi = 0
P2 = 12kΩ
15
I _S (mA)
33
IS
32
10
Vo
31
Figure 14 : Power Dissipation and Efficiency
versus Output Power
3 ^{P tot (W)}
R _L = 16Ω
2.5
η (%)
100
Ptot
80
2
60
η
1.5
40
1
20
Po (W)
0
0
1
2
3
4
5
5
30
Vs (V)
0
29
8
12
16
20
24 28
APPLICATION INFORMATION
(refer to the block diagram)
IF Amplifier-limiter
It is made by six differential stages of 15dB gain
each so that an open loop gain of 90dB is obtained.
While a unity DC gain is provided, the AC closed
loop gain is internally fixed at 70dB that allows a
typical input sensitivity of 50µV.
The differential output signal is single ended by a
20dB gain amplifier that through a buffer stage,
feeds the detector system.
Internal diodes protect the inputs against over-
loads.
- Pin 2 is the IF non-inverting input
- Pin 3 is decoupled by a capacitor to open the AC
loop
- Pin 4 grounded by a capacitor, allows a typical
sensitivity of 50µV. (see VCR facility too).
Low-pass Filter, Fm Detector And Amplifier
The IF signal is detected by converting the fre-
quency modulation into amplitude modulation and
then detecting it.
Since the available modulated signal is a square
wave, a 40 dB/decade low-pass filter cuts its har-
monics so that a sine wave can feed the two-reso-
nances external network L1, C8 and C9.
This network defines the working frequency value,
the amplitude of the recovered audio signal and its
distortion at the highest frequency deviations.
The two resonances f1 (series resonance) and f2
(parallel resonance) can be computed respectively
by :
X_C9
=
X_L1 ⋅
X_L1 +
X_C8
X_C8
and XL1 = XC8
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