Filter Block - Casio SA-65 Service Manual

Filter Block

Since the sound signal from the CPU is a stepped waveform, the filter block is added to smooth the waveform.
To power amp.
Amplifier/Voltage Regulator
(IC101: AN8053N)
The right figure shows the internal block of IC101.
AVDD
Q101
2SC1740SR
C106 R105
AG
AG
— 4 —
R106
5 V
VCC NC CONT VREG
16 15 14 13
5V REG
POWER
SP AMP
1 2 3 4
SPO NC SP GND PC-1 PC-2
From CPU
NC NC NC PRE GND
12 11 10 9
–
VREF
+
5 6 7 8
SPI SPM VREF