— 5 —
Amp.
IC301
Filter Block
Q305/Q306
CPU
LSI1
FILTER BLOCK
Since the sound signal from the CPU is a stepped waveform, the filter block is added to smooth the waveform.
POWER AMPLIFIER (IC301: LA4598)
The power amplifier is a two-channel amplifier with standby switch.
The following table shows the pin function of IC301.
Pin No.
Terminal
In/Out
Function
1
Power GND
In
Ground (0V) source
2
Ch1 B.S.
—
Terminal for a bootstrap capacitor
3
Ch1 OUT
Out
Channel 1 output
4
VCC
In
+9V source
5
Ch1 N.F.
In
Negative feedback input
6
Ch1 IN
In
Channel 1 input
7
D.C.
—
Terminal for a decoupling capacitor
8
Pre GND
In
Ground (0V) source
9
Stand by
In
Power control signal input. 0 V: Off, +9 V: On
10
Ch2 IN
In
Channel 2 input
11
Ch2 N.F.
In
Negative feedback input
12
Ch2 OUT
Out
Channel 2 output
13
Ch2 B.S.
—
Terminal for a bootstrap capacitor
14
NC
—
Not used
LED DRIVING
LG
LVDD
CPU
LSI1
MSM6755B-07
LX0 ~ LX7
LY0 ~ LY7
Q1 ~ Q4
Q5 ~ Q8
Q2 ~ Q4
La ~ Lg
(Common)
(Segment)
MWEB
LED
Latch
IC3
7-segment LED
Keyboard LEDs
LED
Latch
IC2
MD0 ~ MD3
MD4 ~ MD7
MA0
Summary of Contents for CTK-520L
Page 11: ...8 SCHEMATIC DIAGRAMS Main PCB JCM446 MA1M 5 1 6 7 2 3 4...
Page 12: ...9 Sub PCB KDM446 MA2M...
Page 13: ...10 Keyboard PCBs KDM6111K KY1M KY2M...
Page 14: ...11 LED PCB KDM446 LD1M...
Page 15: ...12 LED PCB KDM446 LD2M...
Page 16: ...13 LED PCBs KDM446 LD3M LD4M LD5M KDM446 LD5M KDM446 LD4M KDM446 LD3M...
Page 21: ...MA0800761A Aug 1996...
