FAIRCHILD KA78R08

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KA78R08
Low Dropout Voltage Regulator
Features
Description
•
•
•
•
•
The KA78R08 is a low-dropout voltage regulator suitable
for various electronic equipments. It provides constant voltage power source with TO-220 4 lead full mold package.
Dropout voltage of KA78R08 is below 0.5V in full rated
current(1A). This regulator has various function such as
peak current protection, thermal shut down, overvoltage protection and output disable function.
1A / 8V Output low dropout voltage regulator
TO220 Full-Mold package (4Pin)
Overcurrent protection, Thermal shutdown
Overvoltage protection, Short-Circuit protection
With output disable function
TO-220F-4L
1
1.Vin 2. V O 3. GND 4. Vdis
Internal Block Diagram
Vin
Q1
1
Vo
OVERVOLTAGE
PROTECTION
THERMAL SHUTDOWN
BANDGAP REFERENCE
2
+
R1
SOA PROTECTION
HIGH / LOW
Vdis
4
+
OUTPUT
ON / OFF
R2
1.4V
SHORT-CIRCUIT
SHORTCIRCUIT
PROTECTION
3
GND
Rev. 1.0.1
©2001 Fairchild Semiconductor Corporation
KA78R08
Absolute Maximum Ratings
Parameter
Symbol
Value
Unit
Remark
Input Voltage
Vin
35
V
-
Disable Voltage
Vdis
35
V
-
Output Current
Io
1.0
A
-
Power Dissipation 1
Pd1
1.5
W
No Heatsink
Power Dissipation 2
Pd2
15
W
With Heatsink
Tj
+150
°C
-
Topr
-20 ~ +80
°C
-
Junction Temperature
Operating Temperature
Electrical Characteristics
(Vin =10V, Io = 0.5A, Ta = 25°C , unless otherwise specified)
Parameter
Output Voltage
Symbol
Conditions
Min.
Typ.
Max.
Unit
Vo
-
7.8
8
8.2
V
Load Regulation
Rload
5mA < Io < 1A
-
0.1
2.0
%
Line Regulation
Rline
9V < Vin < 25V
-
0.5
2.5
%
45
55
-
dB
-
-
0.5
V
2.0
-
-
V
Ripple Rejection Ratio
RR
note1
Dropout Voltage
Vdrop
Io = 1A
Disable Voltage High
VdisH
Output Active
Disable Voltage Low
VdisL
Output Disabled
-
-
0.8
V
Disable Bias Current High
IdisH
Vdis = 2.7V
-
-
20
µA
Disable Bias Current Low
IdisL
Vdis = 0.4V
-
-
-0.4
mA
Io = 0A
-
-
10
mA
Quiescent Current
Iq
Note:
1.These parameters, although guaranteed, are not 100% tested in production.
2
KA78R08
Typical Perfomance Characteristics
50
7
6
5
4
RL=8Ω
3
2
40
30
20
8
RL=
8
Quescent
i
current Iq(mA)
9
8
Output voltage Vo(V)
10
RL=
10
1
0
0
5
0
10
15
20
25
0
5
Input voltage Vin (V)
10
15
20
25
Input voltage Vin (V)
Figure 1.Output Voltage vs. Input Voltage
Figure 2.Quiescent Current vs. Input Voltage
10
8.06
8
Output voltage Vo(V)
Output voltage Vo(V)
9
7
6
5
4
3
2
8.04
8.02
8.00
7.98
7.96
7.94
1
0
0.5
1
1.5
2
2.5
7.92
-25
3
0
Disable voltage Vdis (V)
Figure 3.Output Voltage vs. Disable Voltage
50
75
100
125
Figure 4.Output Voltage vs. Temperature(Tj)
Dropout voltage Vdrop(V)
10
Quescent
i
current Iq(mA)
25
TEMPERATURE Tj(oC)
8
6
4
2
0.6
0.5
0.4
Io=1A
0.3
0.75A
0.2
0.5A
0.1
0.25A
0
-25
0
25
50
75
100
125
Junction temperature Tj( oC )
Figure 5.Quiescent Current vs. Temperature(Tj)
0
-25
0
25
50
75
100
125
Junction temperature Tj(o C)
Figure 6.Dropout Voltage vs. Junction Temperature
3
KA78R08
Typical Perfomance Characteristics (continued)
100
Relative output voltage(%)
Power dissipation PDD(W)
20
15
10
5
0
-25
80
60
40
20
0
0
25
50
75
100
125
TEMPERATURE TaJ( oC)
Figure 7.Power Dissipation vs. Temperature(Ta)
0
0.5
1.0
2.0
2.5
Figure 8. Overcurrent Protection Characteristics
(Typical Value)
4
1.5
Output Current(A)
KA78R08
Typical Application
Vo
Vin
1
2
+
+
3
GND
4
Vdis
Disable Signal
Figure 1.Application Circuit
• Ci is required if regulator is located an appreciable distance from power supply filter.
• Co improves stability and transient response.(Co > 47 µF)
5
KA78R08
Mechanical Dimensions
Package
Dimensions in millimeters
TO-220F-4L
6
KA78R08
Ordering Information
Product Number
Package
Operating Temperature
KA78R08
TO-220F-4L
-20 °C to + 80°C
7
KA78R08
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.
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 2001 Fairchild Semiconductor Corporation