— 5 —
LG
LVDD
CPU
LSI1
MSM6755B-13
LX0 ~ LX7
LY1 ~ 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
Amp.
IC301
Filter Block
Q305
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
Содержание CTK-220L
Страница 11: ...9 Sub PCBs KDM445 MA2M MA3M...
Страница 12: ...10 Keyboard PCBs KDM4910K KY1M KY2M...
Страница 13: ...11 LED PCB KDM446 LD1M...
Страница 14: ...12 PCB NAME LED PCB KDM445 LD2M...
Страница 15: ...13 PCB NAME PCB NAME LED PCB KDM446 LD3M LED PCB KDM445 LD4M...
Страница 16: ...11 10 3 4 R 3 R 4 1 14 13 12 2 18 19 15 16 5 6 17 9 7 8 R 2 R 1 EXPLODED VIEW 14...
Страница 19: ...MA1100761A Nov 1996...
