AN8771NFH Datasheet, PDF (9/11 Pages) Panasonic Semiconductor – Pre-amplifier IC for MD

s Technical Data (continued)
4. Internal circuit of APCPD− (pin 63)
REFIN ⁶⁴
APCPD+ 62
61 LDO
V_CC3
AN8771NFH
APCPD− 63
A current mirror circuit of which primary side is APCPD− is built-in. In case where output of secondary side is
connected to APCPD+ and PD current for laser monitor is sunk to PD, the direction of current can be reversed by
connecting the PD output to APCPD− .
Mirror ratio is 1 to 1 as the h_FE = ∞
When using no current mirror, connect APCPD− to V_CC3 .
s Application Circuit Example
PWM signal
Microcomputer
V_REF
49
50
PD _Head
amp.
51
PD
Optical pick-up
52
PD
53
54
PD
PD
55
56
PD
57
PD
V_CC3
PD
58
59
60
PD
61
62
Laser
63
diode
64
V_REF
32 ^VCC1
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
Laser drive reference voltage
V_REF
Temperature sensor
SDD00018CEB
Survo-LSI
9