Casio CTK-680 User Manual

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POWER AMPLIFIER (IC202: LA4598)
The power amplifier is a two-channel amplifier with standby switch.
The following table shows the pin function of IC202.
Pin No. Terminal In/Out Function
28 SAMPB Out Working Storage RAM chip select signal
29, 30 D0, D1 In Data bus
44 K0O In Clock pulse from CPU
A4 ~ A1531 ~ 38, 40 ~ 43 In
Address bus
FILTER BLOCK
Since the sound signals from the DAC are stepped waveforms, the filter block is added to smooth the
waveforms.
AG
AG
R249
2.2K
R247
C223(H)
R245 R243
1K 1K 1K
1K 1K 1K
C244
C152B
C246
C472B
AG
Q207
2SC1740SR
Q208
2SC1740SR
C242
22
Ω R236
AVDD
AG
AG
R250
2.2K
R248 R246 R244
C245
C152B
C247
C472B
AG
C243
C223[H]
From DA ConverterTo Power Amp.
Main
Volume
Pin No. Terminal In/Out Function
1 Power GND In Ground (0 V) source
2 Ch1 B.S. — Terminal for a bootstrap capacitor
3 Ch1 OUT Out Channel 1 output
4 VCC In +9 V 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 (0 V) 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

Casio CTK-680 Specifications

General

Brand	Casio
Model	CTK-680
Category	Keyboard
Language	English