Philips Semiconductors
Dual channel TV FM intercarrier
sound demodulator
Product specification
TDA9821
Notes
1. The output signal at pin 7 can only be measured when mute is disabled. This is achieved by inserting a resistor of
2.7 kΩ between pin 15 and ground. In this event the input impedance is 490 Ω.
2. Improvement of ripple rejection is possible by connecting series RC between pin 11 and pin 14 (15 kΩ + 2.2 µF;
see Fig.5) for a supply voltage of 4.5 to 5.5 V. The rejection of ripple frequencies up to 3 kHz is improved, but up to
200 kHz is worse; see Fig.3.
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RR
(dB)
30
20
MHA530
(1)
(2)
10
0
4
5
6
7
8
VP (V)
9
The curves are typical and valid for ripple frequencies between 50 Hz and 3 kHz.
Conditions: input signal: f = 5.5 MHz, 10 mV (RMS value); ripple on VP = 100 mV (RMS value), fr = 1 kHz;
ripple rejection measurement: unweighted RMS.
(1) Without RC.
(2) With R = 15 kΩ and C = 2.2 µF.
Fig.3 Typical improvement.
1996 Nov 20
8