R= 8

Ω

L

d = 10%

V (V)

s

R= 16

Ω

L

8

10

12

14 1618202224

26 28

0

1

2

3

4

P(W)

tot

Figure 13 : Power Dissipation versus Supply

Voltage (sine wave operation)

P

(W)

tot

P (W)

o

Ptot

η (%)

1

234

5

0

1

1.5

2

2.5

3

0

20

40

60

80

100

R= 16

Ω

L

η

Figure 14 : Power Dissipation and Efficiency

versus Output Power

V(V)

s

8

121620

24

28

0

5

10

15

20

V= 0

P2 = 12k

Ω

i

I S

Vo

I

(mA)

S

29

30

31

32

33

Vo

Figure 15 : Quiescent Drain and Quiescent Out-

put Voltage versus Supply Voltage

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 50

µV.

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 50

µV. (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 :

=

TDA8190

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