Pin Functions
Pin No.
Symbol
LA7566
Pin function
Equivalent circuit
• Audio FM detector output.
Deemphasis is switched internally in the IC. (5 kΩ and 7.5 kΩ)
1
FM DET OUT
This switching is linked to the SIF input switch. An external
emitter-follower circuit must be provided if the deemphasis is
disabled.
• Connection for a filter that holds the FM detector output DC
2
SIF FILTER
voltage at a fixed level. Normally, a 1-µF electrolytic capacitor is
used. To improve the low band (around 50 Hz) frequency
characteristics, increase the value of this capacitor (C1).
• VIF amplifier input.
5
VIF IN
The input circuit is constructed as a balanced input, and the
input has the following impedance characteristics:
6
R ≈ 1.5 kΩ
C ≈ 3 pF
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