cxa1992br Sony Electronics, cxa1992br Datasheet - Page 48

• Manufacturer Part Number: cxa1992br
• Description: Rf Signal Processing Servo Amplifier
• Manufacturer: Sony Electronics

Notes on Operation
1. Focus OK circuit
1) Refer to the "Description of Operation" for the time constant setting of the focus OK amplifier LPF and the
2) The equivalent circuit for the output pin (FOK) is shown in the diagram below.
The FOK and comparator output are as follows:
2. Sled amplifier
The sled amplifier may oscillate when used by the buffer amplifier. Use with a gain of approximately 20dB.
3. Focus/Tracking internal phase compensation and reference design material
4. Laser power control
The RF level is stabilized by attaching an offset to the APC V
RF level fluctuations.
The laser life is shortened by increasing the laser power when the less light is reflected from the disc.
It is recommended that the typical laser power value is set lower to maintain the laser life.
Take care of the laser maximum ratings when using the laser power control circuit.
5. RF amplifier
The phase compensation value in the IC is set on condition that 20 to 30p capacitance of optical pickup and
line material is attached.
In case of voltage output-type pickup, resistor is inserted in series prior to PD1/PD2 pins. It looks capacitance
that attach to PD1/PD2 pins becomes smaller.
At this time, RF amplifier may oscillate. Connect a capacitance around 5 to 20p between PD1/PD2 pins and
GND, and use it.
mirror amplifier HPF.
1.2kHz gain
1.2kHz phase
1.2kHz gain
1.2kHz phase
2.7kHz gain
2.7kHz phase
Output voltage High : V
Output voltage Low : V
Item
08
08
25
25
25
25
FOKH
FOKL
SD
13
13
Vsat (NPN) + V
near Vcc
Measurement pin
13
6
EE
– 48 –
C
C
C
100k
40k
FLB
FGD
TGU
L
Conditions
and controlling the laser power in sync with the
= 0.1µF
= 0.1µF
= 0.1µF
V
EE
V
20k
V
CC
EE
–125
–130
Typ.
21.5
26.5
63
13
FOK
27
V
CC
Unit
R
deg
deg
deg
dB
dB
dB
L
CXA1992BR