
FAN8026D (KA3026D)
8
D
Application Information
1. REFERENCE INPUT
Pin 12 (REF) is a reference Input pin.
1) Reference Input
The applied voltage at the reference input pin must be between 1.5 (V) and 6.5 (V), when Vcc = 8V.
2. SEPARATED CHANNEL MUTE FUNCTION
These pins are used for individual channel mute operation.
1) When the mute pins (pin13,14 and 22) are Low level, the mute circuits are enabled and the output circuits are muted.
2) When the voltage of the mute pins (pin13,14 and 22) are High level, the mute circuits are disabled and the output circuits
operate normally.
3) If the chip temperature rises above 175
°
C, then the thermal shutdown (TSD) circuit is activated and the output circuits are
muted.
Mute1, 2 (pin13) - CH1, 2 mute control input pin.
Mute3 (pin14) - CH3 mute control input pin.
Mute4 (pin22) - CH4 mute control input pin.
3. PROTECTION FUNCTION
Thermal Shutdown (TSD)
1) If the chip temperature rises above 175
°
C the thermal shutdown (TSD) circuit is activated and the output circuit is in the
Mute state, that is Off state.
The TSD circuit has a temperature hysteresis of 25
°
C.
4. FOCUS, TRACKING ACTUATOR, SLED MOTOR DRIVE PART
1) The reference voltage REF is given externally through pin 12.
2) The error amp output signal is amplified by R2/R1 times and then fed to
the level shift circuit.
3) 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), the output signal of the error amp is amplified by (R2/R1)
×
2
×
(1+R4/R3).
4) If the total gain is insufficient, the input error amp can be used to increase
the gain.
5) The bias voltage (Vr) is about a half of the supply voltage(VM).
-
+
LEVEL
SNIFT
Vin
1 4
2 5
3 6 7
EA
+
-
+
-
R1
R2
AP1
+
-
12
Vref
Error Amp
+
+
-
-
AP2
AP3
R3
R3
Vr
R4
R4
Power Amp
M