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KA278RXXC-Series
2A Output Low Dropout Voltage Regulators
Features
KA278RXXC-series (33/05/51/09/12)
• 2A/3.3V, 5V, 5.1V, 9V, 12V output low dropout voltage
regulator
• TO-220 full-mold package (4pin)
• Overcurrent protection, thermal shutdown
• Overvoltage protection, short circuit protection
• With output disable function
Description
The KA278RXXC is a low-dropout voltage regulator suit-
able for various electronic equipments. It provides
constant voltage power source with TO-220-4 lead full mold
package. The dropout voltage of KA278RXXC is below
0.5V in full rated current(2A). This regulator has various
functions such as a peak current protection, a thermal shut
down, an overvoltage protection .
TO-220F-4L
KA278RA05C
•
•
•
•
•
•
Nominal 5V output without adjusting
Output adjustable between 1.25V and 32V
2A output low dropout voltage regulator
TO-220 full-mold package (4pin)
Overcurrent protection, thermal shutdown
Overvoltage protection, short circuit protection
1
1.Vin 2. Vo 3. GND 4. Vdis - KA278RXXC(33/05/51/09/12)
1.Vin 2. Vo 3. GND 4. Vadj - KA278RA05C
Internal Block Diagram
Vin
1
Q1
2
Vo
Vin
1
Q1
2 Vo
THERMAL SHUTDOWN
OVERVOLTAGE
PROTECTION
THERMAL SHUTDOWN
OVERVOLTAGE
PROTECTION
BANDGAP REFERENCE
-
+
R1
BANDGAP REFERENCE
-
+
Rin
SOA PROTECTION
HIGH / LOW
Vdis
4
-
+
OUTPUT
ON / OFF
SOA PROTECTION
4
R2
SHORTCIRCUIT
PROTECTION
Vadj
1.4V
SHORTCIRCUIT
PROTECTION
Rref
3
GND
3
GND
(KA278R33/05/51/09/12C)
(KA278RA05C)
Rev. 1.0.2
©2005 Fairchild Semiconductor Corporation
KA278RXXC-SERIES
Absolute Maximum Ratings
KA278RXXC, KA278RA05C
Parameter
Input voltage
Disable voltage
Output current
Power dissipation 1
Power dissipation 2
Junction temperature
Operating temperature
Thermal resistance, junction-to case (note2)
Thermal resistance, junction-to-air (note2)
KA278RXXC
Symbol
Vin
Vdis
Io
Pd1
Pd2
Tj
Topr
Rθjc
Rθja
Value
35
35
2.0
1.5
15
150
-20 ~ 80
2.9
48.51
Unit
V
V
A
W
W
°C
°C
°C/W
°C/W
Remark
-
-
-
No heatsink
With heatsink
-
-
-
-
2
KA278RXXC-SERIES
Electrical Characteristics
(Vin=Note3, Io=1.0A, Ta=25°C , unless otherwise specified)
Parameter
KA278R33C
KA278R05C
Output voltage
KA278R51C
KA278R09C
KA278R12C
Load regulation
Line regulation
Ripple rejection ratio
Dropout voltage
Disable voltage high
Disable voltage low
Disable bias current low
Quiescent current
Reference voltage
KA278RA05C
KA278RXXC
KA278RXXC
KA278RXXC
Rload
Rline
RR
Vdrop
VdisH
VdisL
IdisH
IdisL
Iq
Vref
Note4
Note1
Io = 2A
Output active
Output disabled
Vdis = 2.7V
Vdis = 0.4V
Io = 0A
-
Vo
Symbol
Conditions
-
-
-
-
-
5mA < Io < 2A
Min.
3.22
4.88
4.98
8.78
11.7
-
-
45
-
2.0
-
-
-
-
1.24
Typ.
3.3
5
5.1
9
12
0.1
0.5
55
-
-
-
-
-
-
1.27
Max.
3.38
5.12
5.22
9.22
12.3
2.0
2.5
-
0.5
-
0.8
20
-0.4
10
1.30
%
%
dB
V
V
V
µA
mA
mA
V
V
Unit
Disable bias current high KA278RXXC
Note:
1.These parameters, although guaranteed, are not 100% tested in production.
2. Junction -to -case thermal resistance test environments.
-. Pneumatic heat sink fixture.
-. Clamping pressure 60psi through 12mm diameter cylinder.
-. Thermal grease applied between PKG and heat sink fixture.
3. KA278R33C : Vin = 5V
KA278R05C : Vin = 7V
KA278R09C : Vin = 11V
KA278R12C : Vin = 15V
4. KA278R33C : Vin =4 to 10V
KA278R05C, KA278R51C : Vin=6 to 12V
KA278R09C : Vin=10 to 25V
KA278R12C : Vin = 13V to 29V
3
KA278RXXC-SERIES
Typical Performance Characteristics
KA278R33C
5.25
100
80
60
40
20
RL=
∞
Output voltage Vo(V)
4.50
3.75
3.00
2.25
1.50
0.75
0
RL=3.3Ω
RL=
8
Quiescent current Iq(mA)
0
0
2
4
6
8
10
0
5
10
Input voltage Vin(V)
15
20
Input voltage Vin (V)
Figure 1. Output Voltage vs. Input Voltage
5.25
Figure 2. Quiescent Current vs. Input Voltage
3.36
Output voltage Vo(V)
0
0.5
1
1.5
2
2.5
3
Output voltage Vo(V)
4.50
3.75
3.00
2.25
1.50
0.75
0
3.34
3.32
3.30
3.28
3.26
3.24
3.22
-25
0
Disable voltage Vdis (V)
75
25
50
TEMPERATURE Tj(
o
C)
100
125
Figure 3. Output Voltage vs. Disable Voltage
10
Figure 4. Output Voltage vs. Temperature(Tj)
Quiescent current Iq(mA)
0.70
8
Drop out voltage Vdrop [V]
0.65
0.60
0.55
0.50
0.45
0.40
0.35
0.30
-25
0
25
50
75
100
125
2.0A
6
4
2
0
-25
0
25
50
75
100
125
Junction temperature Tj(
o
C)
Junction Temp Tj [
℃
]
Figure 5. Quiescent Current vs. Temperature(Tj)
Figure 6. Dropout Voltage vs.Junction Temperature
4
KA278RXXC-SERIES
Typical Performance Characteristics
(Continued)
20
100
Relative output voltage(%)
Power dissipation P
D
(W)
80
60
15
10
40
5
20
0
-25
0
0
75
25
50
TEMPERATURE Tj(
o
C)
100
125
0
1.0
2.0
3.0
4.0
5.0
6.0
Output Current(A)
Figure 7. Power Dissipation vs. Temperature(Tj)
Figure 8. Overcurrent Protection Characteristics
(Typical Value)
4.75
Output peak current Iop (A)
4.50
4.25
4.00
3.75
3.50
0
1
2
3
4
5
6
Input-output differential voltage Vin-Vo (V)
Figure 9. Output Peak Currenrt vs.
Input-Output Differential Voltage
5
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