KA3027D2 データシートの表示（PDF） - Fairchild Semiconductor
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KA3027D2 Datasheet PDF : 14 Pages
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KA3027D2
Application Information
1. REFERENCE INPUT
Pin 26 (REF) is a reference Input pin.
1) Reference Input
The applied voltage at the reference input pin must be between 1.5 (V) and 3.5 (V), when Vcc = 5V.
2. SEPARATED CHANNEL MUTE FUNCTION
These pins are used for individual channel mute operation.
1) When the mute pins (pin27, 28 and 8) are Low level, the mute circuits are enabled and the output circuits are muted.
2) When the voltages of the mute pins (pin27, 28 and 8) 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 (pin 27)-CH1, 2 mute control input pin.
Mute3 (pin 28)-CH3 mute control input pin. Mute4(pin8) - 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
CIRCUIT
1) The reference voltage REF is given externally through pin 26.
2) The error amp output signal is amplified by R2/R1 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).
M
Power Amp
R4
-AP2+
+AP3-
R4
Vr
R3
R3
-
+
LEVEL SNIFT
26
+
+AP1-
R2
-
R1
Vref
17 20 21
Error Amp
EA
+-
Vin
15 18
16 19
8
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