CXA2647N
• Focus Error
The signals input to the A and C pins and the B and D pins are arithmetically amplified and the focus error
signal is output.
This circuit has ROM/RW switching and offset addition functions.
VC
100k
ROM
23.5k
30k
RW
FEI 17
124
16 FE
124
100k
A
C
B
D
6
8
7
9
50k
30k
30k
ROM
RW
DVC
30k
47k
ROM
47k
200k
VOFST
RW
200k
FE = Gain { (B + D) – (A + C) }
Low frequency gain ROM: 15.5dB
RW: 27.5dB
Cut-off frequency fc (typ.) ROM: 400kHz
RW: 300kHz
• Tracking Error
The signals input to the E and F pins are arithmetically amplified and the tracking error signal is output.
This circuit has ROM/RW switching and offset addition functions.
VC
Control bias
VC – 1V to VC + 1V
TE = Gain (F – E)
19
TE_BAL
Low frequency gain ROM: 16dB
RW: 28dB
63k ROM
63k
ROM
VOFST
VC
RW
20k
251k
20k
20k
RW
251k
F
E
TE balance adjustment
(F – E) low frequency gain = ±6dB
gm
gm
11
10
10k
18
TE
Cut-off frequency fc (typ.)
ROM: 200kHz
20k
10k
RW: 150kHz
VC
31.5k
125.5k
RW
ROM
VC
External resistance value vs. Low frequency gain for E and F input pins
22
15.5
12.5
10k
20k
30k
Resistance value [Ω]
– 11 –
SONY [ SONY CORPORATION ]
