AN8808SB Datasheet, PDF (6/10 Pages) Panasonic Semiconductor – Three-Beam Method Head Amplifier IC for CD supporting the hologram pick-up

AN8808SB
ICs for CD/CD-ROM Player
s Operational Description (The values shown below are design values when supply voltageVCC=5V.)
• RF Amplifier
As shown in Figure 1, RF signals are generated by three-beam method pick-up. Equivalent resistance to RFOUT (Pin7) is
127kΩ, when resistance between RF– and RFOUT is 12kΩ.
106kΩ
Light level
12kΩ
AB
DC
36
–
+
106kΩ
35
–
RRF
6
7
10kΩ
–
10kΩ
+
Dark level
+
RRF(T)=106kΩ ×
RRF
10kΩ
Figure 1 : RF Amplifier
• Focus Error Amplifier
As shown in Figure 2, the operation result of (A + C) – (B + D) is outputted to FEOUT (Pin27). Equivalent resistance to
FEOUT is 212kΩ, when resistance between FE and FEOUT is 20kΩ.
AB
DC
106kΩ
VCBA
36
–
A+C
+
106kΩ
Subtraction
20kΩ
RFE
28
27
–
B+D
+
35
–
+
29
–
VC
+
Figure 2 : Focus Error Amplifier