Aiwa XR–DV525 Service Manual page 33

IC, LC72131D
Pin No. Pin Name
1 X-IN
22 X-OUT
2 NC
3 CE
4 DI
5 CL
6 DO
7 T-BASE
8 MONO / BEAT
9 FM / SW
10 MW / SW
11 IF-MUTE
12 IF-IN
13 TUNE
14 NC
15 AM-IN
16 FM-IN
17 VDD
18 PD
19 A-IN
20 A-OUT
21 VSS
I/O
I
A crystal oscillator (4.5MHz) is connected between these pins.
O
– Not connected.
I To enable the IC. Active "H".
Digital data input from CPU (LC876572V-5T19) when relevant key is operated.
I
Active "H".
I To clock in the data DI.
O Digital data output to CPU (LC876572V-5T19).
O Outputs a reference clock signal (8Hz) for the clock.
O Outputs "H" when MONO / BEAT is switched.
Output "L" or "H" as follows:
2 BAND
O
AM FM LW
H L H
Outputs "L" or "H" as follows:
2 BAND
O
AM FM LW
L L H
O To control internal counter.
I General purpose counter input.
I Receives "L" when station is tuned.
– Not connected.
I Receives the AM local oscillator frequency signal.
I Receives the FM local oscillator frequency signal.
– Supply power to IC (+5V).
O PLL charge pump output.
I
The MOS transistor used for PLL active low pass filter.
O
– Ground.
Description
3 BAND 3 BAND
MW FM MW
H L H
3 BAND 3 BAND
MW FM MW
L L L
– 33 –
SW FM
L L
SW FM
H L