KA3021D
3. FOCUS, TRACKING ACTUATOR, SLED MOTOR DRIVE PART
M
Power amp
R4
AP2
Vr
R3
AP3
R4
R3
−
LEVEL
+
SHIFT
AP1
R2
23
−
Vref
4 24
R1
3 20 25
• The reference voltage REF is given externally through pin 23.
• The input signal,pin3,20.25 is amplified by R2 / R1 times and then fed to the level shift circuit.
• The level shift circuit produces the differential output voltages and drives the two output power amplifiers. Since the
differential gain of the output amplifiers is equal to 2 × (1+ R4 / R3), input signal is amplified by (R2 / R1) × 2 × (1 + R4 /
R3).
• If the total gain is insufficient, the external resistors can be used through pin 4, 24 to increase the gain.
• The bias voltage (Vref) is about a half of the supply voltage(VM).
4. TRAY MOTOR DRIVE PART
DO2+
M
12
DO2−
13
D
D
LEVEL SHIFT
CTL
M.S.C
19
S.W
IN
FWD
16
IN
REV
15
9