LA75525AVA
Continued from preceding page.
Pin No. Pin name
Function
20 RF AGC VR
RF AGC VR connection.
This pin sets the tuner RF AGC operating point Also, the FM
output and the video output can both be muted the same time by
connecting this pin to GND.
21 SIF BPF
OUTPUT
The output to the external band-pass filter is passed through an
internal 6dB amplifier before being output.
Equivalent circuit
VCC
3.6V
1kΩ
1kΩ
20
VCC
100Ω
21
22 AUDIO BIAS
FILTER
Connection for a filter used to hold the FM detector output DC
voltage fixed. Normally, a 1µF electrolytic capacitor should be
used. The capacitance should be increased if the low band
(around 50Hz) frequency characteristics need to be improved.
The FM detector output level can be reduced and the FM
dynamic range can be increased by inserting a resistor and a
capacitor in series between pin 22 and GND.
300Ω
22
23 FILTER
CONTROL C
Internal sound carrier TRAP are tuned using the capacitor
connected to pin 23.
A value between 0.47µF and 1µF is considered desirable taking
video S/N, and AM and PM noise into consideration.
24 AUDIO
OUTPUT
Audio FM detector output. A 54kΩ resister is inserted in series
with an emitter-follower output.
For applications that support mono:
Create an external de-emphasis circuit.
t = C1 × R1
VCC
R1
24
C1
300Ω 20KΩ
20KΩ
500Ω
500Ω
23
20KΩ
400Ω
54kΩ
6kΩ
No.A1256-9/10