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KA78R12
Low Dropout Voltage Regulator
Features
· · · · · 1A / 12V Output low dropout voltage regulator TO220 Full-Mold package (4PIN) Overcurrent protection, Thermal shutdown Overvoltage protection, Short-Circuit protection With output disable function
Description
The KA78R12 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 KA78R12 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.
TO-220F-4L
1
1. Vin 2. Vo 3. GND 4. Vdis
Internal Block Diagram
Q1
Vin
1
2
Vo
THERMAL SHUTDOWN
OVERVOLTAGE PROTECTION
BANDGAP REFERENCE
+ 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
KA78R12
Absolute Maximum Ratings
Parameter Input Voltage Disable Voltage Output Current Power Dissipation 1 Power Dissipation 2 Junction Temperature Operating Temperature Symbol Vin Vdis Io Pd1 Pd2 Tj Topr Value 35 35 1.0 1.5 15 +150 -20 ~ +80 Unit V V A W W °C °C Remark No Heatsink With Heatsink -
Electrical Characteristics
(Vin =15V, Io = 0.5A, Ta = 25°C , unless otherwise specified) Parameter Output Voltage Load Regulation Line Regulation Ripple Rejection Ratio Dropout Voltage Disable Voltage High Disable Voltage Low Disable Bias Current High Disable Bias Current Low Quiescent Current Symbol Vo Rload Rline RR Vdrop VdisH VdisL IdisH IdisL Iq 5mA < Io < 1A 13V < Vin < 29V note1 Io = 1A Output Active Output Disabled Vdis = 2.7V Vdis = 0.4V Io = 0A Conditions Min. 11.7 45 2.0 Typ. 12 0.1 0.5 55 Max. 12.3 2.0 2.5 0.5 0.8 20 -0.4 10 Unit V % % dB V V V µA mA mA
Note: 1.These parameters, although guaranteed, are not 100% tested in production.
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KA78R12
Typical Perfomance Characteristics
17.5 50
Output voltage Vo(V)
15.0 12.5
RL= 8
Quescent current Iq(mA) i
40
10.0 7.5
RL=12
30
20
RL=
5.0 2.5 0 0 5 10 15 20 25
10
0
0
5
10
8 15
20
25
Input voltage Vin (V)
Input voltage Vin (V)
Figure 1.Output Voltage vs. Input Voltage
Figure 2.Quiescent Current vs. Input Voltage
17.5
12.06 12.04 12.02 12.00 11.98
Output voltage Vo(V)
15.0 12.5 10.0 7.5 5.0 2.5 0 0 0.5 1 1.5 2 2.5 3
Output voltage Vo(V)
11.96
11.94 11.92 -25
0
25
50
75
100
125
Disable voltage Vdis (V)
TEMPERATURE Tj(oC)
Figure 3.Output Voltage vs. Disable Voltage
Figure 4.Output Voltage vs. Temperature(Tj)
Quescent current Iq(mA) i
Dropout voltage Vdrop(V)
10 8
0.6 0.5 0.4 Io=1A 0.3 0.75A 0.2 0.5A 0.1 0.25A 0 -25
6
4
2
0
-25
0
25
50
75
100
125
0
25
50
75
100
125
Junction temperature Tj( oC)
Junction temperature Tj(o C)
Figure 5.Quiescent Current vs. Temperature(Tj)
Figure 6.Dropout Voltage vs. Junction Temperature
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KA78R12
Typical Perfomance Characteristics (continued)
20 100
Power dissipation PDD(W)
Relative output voltage(%)
80 60
15
10
40
5
20
0 -25
0 0 25 50 75 TJ( oC) 100 125 TEMPERATURE
0
0.5
1.0
1.5
2.0
2.5
3.0
a
Output Current(A)
Figure 7.Power Dissipation vs. Temperature(Ta)
Figure 8. Overcurrent Protection Characteristics (Typical Value)
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KA78R12
Typical Application
Vin 1
+
Vo 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)
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KA78R12
Mechanical Dimensions
Package Dimensions in millimeters
TO-220F-4L
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KA78R12
Ordering Information
Product Number KA78R12 Package TO-220F-4L Operating Temperature -20 °C to + 80°C
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