KA278RA05 [FAIRCHILD]
Low Dropout Voltage Regulator (Fixed & Adjustable); 低压差稳压器（固定式和可调）
| 型号： | KA278RA05 |
| 厂家： | 
FAIRCHILD SEMICONDUCTOR |
| 描述： | Low Dropout Voltage Regulator (Fixed & Adjustable) |
| 文件： | 总8页 (文件大小：79K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
www.fairchildsemi.com
KA278RA05
Low Dropout Voltage Regulator
(Fixed & Adjustable)
Features
Description
• Nominal 5V output without adjusting
• Output Adjustable Between 1.25V and 32V
• 2A Output low dropout voltage regulator
• TO220 Full-Mold package (4PIN)
• Overcurrent protection, Thermal shutdown
• Overvoltage protection, Short-Circuit protection
The KA278RA05 is a low-dropout voltage regulator suitable
for various electronic equipments. It provides constant
voltage power source with TO-220F-4 lead full mold
package. Dropout voltage of KA278RA05 is below 0.5V in
full rated current(2A). This regulator has various function
such as peak current protection, thermal shut down and over
voltage protection.
TO-220F-4L
1
1. Vin 2. V 3. GND 4. Vadj
O
Internal Block Diagram
Q1
Vin
1
2
Vo
OVERVOLTAGE
PROTECTION
THERMAL SHUTDOWN
BANDGAP REFERENCE
-
Rin 1.8kΩ
R1
+
SOA PROTECTION
4
Vadj
SHORT-CIRCUIT
PROTECTION
0.6kΩ
R2
R
3
GND
Rev. 1.0.2
©2001 Fairchild Semiconductor Corporation
KA278RA05
Absolute Maximum Ratings
Parameter
Symbol
Value
35
Unit
V
Remark
Input Voltage
Vin
-
Output Current
I
2.0
A
-
O
Power Dissipation 1
Power Dissipation 2
Junction Temperature
Operating Temperature
Pd1
Pd2
Tj
1.5
W
No Heatsink
15
W
With Heatsink
150
°C
°C
-
-
Topr
-20 ~ 80
Electrical Characteristics
(Vin =7V, I =1.0A, Ta = 25 °C, unless otherwise specified)
O
Parameter
Symbol
Vo
Conditions
Min.
Typ.
Max.
5.12
2.0
2.5
-
Unit
V
Output Voltage
-
4.88
5
0.1
0.5
55
-
Load Regulation
Line Regulation
Ripple Rejection Ratio
Dropout Voltage
Quiescent Current
Reference Voltage
Rload
Rline
RR
5mA < I < 2A
-
%
O
6V < Vin < 12V
note1
-
45
-
%
dB
V
Vdrop
Iq
I
I
= 2A
= 0A
0.5
10
O
O
-
-
mA
V
Vref
-
1.24
1.27
1.30
Note:
1. These parameters, although guaranteed, are not 100% tested in production.
2
KA278RA05
Typical Perfomance Characteristics
7
50
40
6
5
RL=
4
30
20
10
0
RL=2.5Ω
3
2
RL=
1
0
10
0
5
15
5
10
15
0
Input voltage Vin (V)
Input voltage Vin (V)
Figure 1. Output Voltage vs. Input Voltage
Figure 2. Quiescent Current vs. Input Voltage
5.06
10
8
5.04
5.02
6
4
2
0
5.00
4.98
4.96
4.94
4.92
75
-25
0
25
50
100
125
75
TEMPERATURE Tj(oC)
-25
0
25
50
100
125
Junction temperature Tj(oC )
Figure 3. Output Voltage vs. Temperature(Tj)
Figure 4. Quiescent Current vs. Temperature(Tj)
*Fixed Mode (V =5V)
O
0.6
0.5
0.4
20
15
Io=2A
0.3
0.2
0.1
10
5
1.5A
1.0A
0.5A
0
0
-25
75
-25
0
25
50
100
125
75
TEMPERATURE Ta(oC)
0
25
50
100
125
Junction temperature Tj(oC)
Figure 5. Dropout Voltage vs. Junction Temperature
Figure 6. Power Dissipation vs. Temperature(Ta)
3
KA278RA05
Typical Perfomance Characteristics
100
80
60
40
20
0
3.0
0
1.0
2.0
4.0
5.0
6.0
Output Current(A)
Figure 7. Overcurrent Protection Characteristics
(Typical Value)
4
KA278RA05
Typical Application
Output
Input
Vo
2
Vin
1
R3
R4
KA278RA05
GND
Vadj 4
Ci
Co
RL
3
R1//R3
R2//R4
Vo = 1.25 ( 1 +
) R1 = 1.8kΩ , R2 = 0.6kΩ
Figure 7. Application Circuit (Adjustable Mode)
• Ci is required if regulator is located an appreciable distance from power supply filter.
• Co improves stability and transient response.(C > 47µF)
O
25
20
15
10
5
0
-5
-10
50
Junction temperature Tj(℃)
-50
-25
0
25
75
100 125
Figure 8. Internal Resistor(R1,R2) Variation vs. Temperature(Tj)
Output = 5V
Input
Vo
2
4
Vin
1
KA278RA05
GND
Vadj
Ci
Co
RL
3
Figure 9. Application Circuit (Fixed Mode)
5
KA278RA05
Mechanical Dimensions
Package
Dimensions in millimeters
TO-220F-4L
6
KA278RA05
Ordering Information
Product Number
Package
Operating Temperature
KA278RA05
TO-220F-4L
-20°C to + 80°C
7
KA278RA05
DISCLAIMER
FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY
PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY
LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER
DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS.
LIFE SUPPORT POLICY
FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES
OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR
CORPORATION. As used herein:
1. Life support devices or systems are devices or systems
which, (a) are intended for surgical implant into the body,
or (b) support or sustain life, and (c) whose failure to
perform when properly used in accordance with
instructions for use provided in the labeling, can be
reasonably expected to result in a significant injury of the
user.
2. A critical component in any component of a life support
device or system whose failure to perform can be
reasonably expected to cause the failure of the life support
device or system, or to affect its safety or effectiveness.
www.fairchildsemi.com
11/16/01 0.0m 001
Stock#DSxxxxxxxx
2001 Fairchild Semiconductor Corporation
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