©2005 Fairchild Semiconductor Corporation
www.fairchildsemi.com
Rev. 1.0.2
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)
• Ov ercurrent pr otec t ion, therma l shutdown
• Overvoltage protection, short circuit protection
• With output disable function
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)
• Ov ercurrent pr otec t ion, therma l shutdown
• Overvoltage protection, short circuit protection
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
1.Vin 2. Vo 3. GND 4. Vdis - KA278RXXC(33/05/51/09/12)
1
1.Vin 2. Vo 3. GND 4. Vadj - KA278RA05C
Internal Block Diagram
THERM AL SHUTDOW N
BANDG AP RE FE RENCE
OVERVOLTAGE
PROTECTION
SOA PROTECTION
SHORTCIRCUIT
PROTECTION
1
4
3
2
Vin
Vadj
Vo
GND
Q1
Rin
Rref
+
-
THERMAL SHUTDOWN
BANDGAP REFERENCE
OVERVOLTAGE
PROTECTION
SOA PROTECTION
SHORTCIRCUIT
PROTECTION
1
4
3
2
Vin
Vdis
Vo
GND
HIGH / LOW OUTPUT
ON / OFF
Q1
R1
R2
-
+
-
+
1.4V
(KA278RA05C)
(KA278R33/05/51/09/12C)
KA278RXXC-Series
2A Output Low Dropout Voltage Regulator s
KA278RXXC-SERIES
2
Absolute Maximum Ratings
KA278RXXC, KA278RA05C
Parameter Symbol Value Unit Remark
Input voltage Vin 35 V -
Disable voltage KA278RXXC Vdis 35 V -
Output current Io 2.0 A -
Power dissipation 1 Pd1 1.5 W No heatsink
Power dissipation 2 Pd2 15 W With heatsink
Junction temperature Tj 150 °C-
Operating temperature Topr -20 ~ 80 °C-
Thermal resistance, junction-to case (note2) Rθjc 2.9 °C/W -
Thermal resistance, junction-to-air (note2) Rθja 48.51 °C/W -
KA278RXXC-SERIES
3
Electrical Characteristics
(Vin=Note3, Io=1.0A, Ta=25°C , unless otherwise specified)
Note:
1.These parameters, although guaranteed, are not 100% tested in production.
2. Junction -to -case thermal resistance test environments.
-. Pneumatic heat si nk fi xture.
-. Clamping pressure 60p si through 12m m di am et er cylinder.
-. Therma l grea se appl ied betwe en PKG and hea t sink fixtur e.
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
Parameter Symbol Conditions Min. Typ. Max. Unit
Output voltage
KA278R33C
Vo
- 3.22 3.3 3.38
V
KA278R05C - 4.88 5 5.12
KA278R51C - 4.98 5.1 5.22
KA278R09C - 8.78 9 9.22
KA278R12C - 11.7 12 12.3
Load regulation Rload 5mA < Io < 2A - 0.1 2.0 %
Line regulation Rline Note4 - 0.5 2.5 %
Ripple rejection ratio RR Note1 45 55 - dB
Dropout voltage Vdrop Io = 2A - - 0.5 V
Disable voltage high KA278RXXC VdisH Output active 2.0 - - V
Disable voltage low KA278RXXC VdisL Output disabled - - 0.8 V
Disable bias current high KA278RXXC IdisH Vdis = 2.7V - - 20 µA
Disable bias current low KA278RXXC IdisL Vdis = 0.4V - - -0.4 mA
Quiescent current Iq Io = 0A - - 10 mA
Reference voltage KA278RA05C Vref - 1.24 1.27 1.30 V
KA278RXXC-SERIES
4
Typical Performance Characteristics
KA278R33C
Input voltage Vin (V)
4.50
3.75
3.00
2.25
1.50
0.75
5.25
00 2 4 6 8 10
Output voltage Vo(V)
RL=
RL=3.3Ω
8
0 5 10 15 20
0
20
40
60
80
100
∞
RL=
Qu ie sce nt c u rrent Iq(m A )
Input voltage Vin(V)
0
Output voltage Vo( V)
3
Disable voltage Vdis (V)
0.5 1.5
122.5
4.50
3.75
3.00
2.25
1.50
0.75
5.25
0
3.34
3.32
3.30
3.36
-25
Output volta ge Vo(V)
TEMPERATURE Tj(
o
C)
75 125
02550 100
3.26
3.24
3.22
3.28
10
8
6
4
2
0
Quiescent current Iq(mA)
Junction temperat ure Tj(
o
C)
75 125
02550 100
-25
-25 0 25 50 75 100 125
0.30
0.35
0.40
0.45
0.50
0.55
0.60
0.65
0.70
2.0A
Drop out voltage Vdrop [V]
Junction Temp Tj [
!
!!
!
]
Figure 1. Output Voltage vs. Input Voltage Figure 2. Quiescent Current vs. Input Voltage
Figure 4. O u tput Voltage vs. Tempe ratur e(Tj)
Figure 3. Output V olt age vs. Disable Voltage
Figure 5. Quiescent Current vs. Temperature(Tj) Figure 6. Dropout Vo ltage vs.Junct ion Temperat ure
KA278RXXC-SERIES
5
Typical Performance Characteristics
(Continued)
-25
Power dissipation P
D
(W)
TEMPERATURE Tj(
o
C)
75 125
02550 100
15
10
5
20
0
Output Current(A)
Relative output voltage(%)
3.0 5.0
01.02.0 4.0
80
60
20
100
0
40
6.0
Output Current(A)
Relative output voltage(%)
3.0 5.0
01.02.0 4.0
80
60
20
100
0
40
6.0
Relative output voltage(%)
3.0 5.0
01.02.0 4.0
80
60
20
100
0
40
6.0
0123456
3.50
3.75
4.00
4.25
4.50
4.75
Output peak current Iop (A)
Input-output differential voltage Vin-Vo (V)
Figure 9. Output Peak Currenrt vs.
Input-Output Differential Vo ltage
Figure 7. Power Dissipation vs. Temperature(Tj) Figure 8. Overcur rent Prote ction Character i st ics
(Typical Value)
KA278RXXC-SERIES
6
Typical Performance Characteristics
(Continued)
KA278R05C
51015
Input voltage Vin (V)
6
5
4
3
2
1
7
00
Output voltage Vo(V)
RL=
RL=2.5
Ω
8
0 5 10 15 20
0
20
40
60
80
100
120
∞
RL=
Qu ies c e n t cu rre n t Iq (m A )
Input voltage Vin(V)
7
6
5
4
3
00
Output voltage Vo(V)
3
Disable voltage Vdis (V)
0.5 1.5
2
1
122.5
5.04
5.02
5.00
5.06
-25
Output volta ge Vo(V)
TEMPERATURE Tj(
o
C)
75 125
02550 100
4.96
4.94
4.92
4.98
8
6
4
2
0
Quiescent current Iq(mA)
Junction temperature Tj(
o
C)
75 125
02550 100
-25
-25 0 25 50 75 100 125
0.30
0.35
0.40
0.45
0.50
0.55
0.60
0.65
0.70
2.0A
Drop out voltage Vdrop [V]
Junction Temp Tj [
!
!!
!
]
Figure 1. Output Voltage vs. Input Voltage Figure 2. Quiescent Current vs. Input Voltage
Figure 4. Output Voltage vs. Temperature(Tj)
Figure 3. Output Voltage vs. Disable Voltage
Figure 5. Quiescent Current vs. Temperature(Tj) Figure 6. Dropout Vo ltage vs.Junction Temperature
KA278RXXC-SERIES
7
Typical Performance Characteristics
(Continued)
-25
Power dissipation P
D
(W)
TEMPERATURE Tj(
o
C)
75 125
02550 100
15
10
5
20
0
Output Current(A)
Relative output volt age(%)
3.0 5.0
01.02.0 4.0
80
60
20
0
40
6.0
Output Current(A)
Relative output volt age(%)
3.0 5.0
01.02.0 4.0
80
60
20
0
40
6.0
0123456
3.50
3.75
4.00
4.25
4.50
4.75
Output peak current Iop (A)
Input-output differential voltage Vin-Vo (V)
Figure 7. Power Dissipation vs. Temperature(Tj) Figure 8. Overcur rent Prote ction Char acteri st ics
(Typical Value)
Figure 9. Output Peak Currenrt vs.
Input-O u tpu t Differen tia l Voltag e
KA278RXXC-SERIES
8
Typical Performance Characteristics
(Continued)
KA278R51C
51015
Input voltage Vin (V)
6
5
4
3
2
1
7
00
Output voltage Vo(V)
RL=
RL=2.5Ω
ΩΩ
Ω
8
0 5 10 15 20
0
20
40
60
80
100
120
∞
RL=
Quiescent current Iq(mA)
Input voltage Vin(V)
7
6
5
4
3
00
Output volta ge Vo(V)
3
Disable voltage Vdis (V)
0.5 1.5
2
1
122.5
5.14
5.12
5.10
5.16
-25
Output v oltage Vo( V)
TEMPERATURE Tj(
o
C)
75 125
02550 100
5.06
5.04
5.02
5.08
10
8
6
4
2
0
Quescent current Iq( mA)
Junction temperature Tj(
o
C)
75 125
02550 100
-25
-25 0 25 50 75 100 125
0.30
0.35
0.40
0.45
0.50
0.55
0.60
0.65
0.70
2.0A
Drop out voltage Vdrop [V]
Junction Temp Tj [
!
!!
!
]
Figure 1. Output Voltage vs. Input Voltage Figure 2. Quiescent Current vs. Input Voltage
Figure 4. Output Voltage vs. Temperature(Tj)
Figure 3. Output Voltage vs. Disable Vo ltage
Figure 5. Quiescent Current vs. Temperature(Tj) Figure 6. Dropo ut Voltage v s. Junc tion Temperature
KA278RXXC-SERIES
9
Typical Performance Characteristics
(Continued)
-25
Power dissipation P
D
(W)
TEMPERATURE Tj(
o
C)
15
10
5
20
0
Relative output voltage(%)
Output Current(A)
3.0 5.0
01.02.0 4.0
80
60
20
100
0
40
6.0
10
Ripple Reje c tion RR (dB)
Input Ripple Frequency (KHz)
50
40
30
20
00.1 100110
60
70
T
j
= 25
o
C
V
IN
= 7V
I
O
=1A
∆V
IN
= 0.5V
rms
Time (µs)
20
15
10
5
70
Input Voltage (V)
515
25
30
0
-5
-10
-15
-20
-25
8
25 35
Output Voltage
Deviation (mV)
45
Time ( µs)
2.0
1.5
1.0
0.5
00
Output Current (A)
10 20
2.5
3.0
0.0
-0.5
-1.0
-1.5
-2.0
-2.5
2.0
30 40
Output Vol tage
Deviation (V)
0123456
3.50
3.75
4.00
4.25
4.50
4.75
Output peak current Iop (A)
Input-output differential voltage Vin-Vo (V)
Figure 7. Power Dis sipation vs. Temperatu re(Tj ) Figure 8. Overcurrent Protection Characteristics
Figure 9. Ripple Rejecti on vs. Input Ripple Frequency Figure 10. Line Transient Response
Figure 11. Load Transient Response
(Typical value)
Figure 12. Output Peak Currenrt vs.
Input-Output Differential Voltage
KA278RXXC-SERIES
10
Typical Performance Characteristics
(Continued)
KA278R09C
10
8
6
4
2
00
Output voltage Vo(V)
20
Input v oltage V in ( V)
510
RL=
RL=4.5Ω
15
8
0 5 10 15 20
0
20
40
60
80
100
120
∞
RL=
Quiescent current Iq(mA)
Input voltage Vin(V)
0
Output voltage Vo (V)
3
Disable voltage Vdis (V)
0.5 1.5
122.5
10
8
6
4
2
0
9.08
9.04
9.00
9.12
-25
Output v oltage Vo( V)
TEMPERATURE Tj(
o
C)
75 125
02550 100
8.92
8.88
8.84
8.96
10
8
6
4
2
0
Quescent current Iq( mA)
Junction temperature Tj(
o
C)
75 125
02550 100
-25
-25 0 25 50 75 100 125
0.30
0.35
0.40
0.45
0.50
0.55
0.60
0.65
0.70
2.0A
Drop out voltage Vdrop [V]
Junction Temp Tj [
!
!!
!
]
Figure 1. Output Voltage vs. Input Voltage Figure 2. Quiescent Current vs. Input Voltage
Figure 3. Output Voltage vs. Disable Voltage Figure 4. Output Voltage vs. Tempe rature(Tj)
Figure 5. Quiescent Current vs. Temperature(Tj) Figure 6. Dr opout Voltage vs.Ju nction Te m perature
KA278RXXC-SERIES
11
Typical Performance Characteristics
(Continued)
-25
Power dissipation P
D
(W)
TEMPERATURE Tj(
o
C)
75 125
02550 100
15
10
5
20
0
Output Current(A)
6.0
Relative output voltage(%)
3.0 5.0
01.02.0 4.0
80
60
20
100
0
40
Output Current(A)
6.0
Relative output voltage(%)
3.0 5.0
01.02.0 4.0
80
60
20
100
0
40
6.0
Relative output voltage(%)
3.0 5.0
01.02.0 4.0
80
60
20
100
0
40
0123456
3.50
3.75
4.00
4.25
4.50
4.75
Output peak current Iop (A)
Input-output differential voltage Vin-Vo (V)
Figure 7. Power Dis sipation vs. Temperatu re(Tj ) Figure 8. Overcurrent Protection Characteristics
(Typical Value)
Figure 9. Output Peak Currenrt vs.
Input- Ou tp ut Dif ferentia l Voltage
KA278RXXC-SERIES
12
Typical Performance Characteristics
(Continued)
KA278R12C
51015
Input voltage Vin (V)
15.0
12.5
10.0
7.5
5.0
2.5
00
Output volt age Vo(V)
RL=
RL= 6Ω
20 25
8
0 5 10 15 20
0
20
40
60
80
100
120
∞
RL=
Quiescent current Iq(mA)
Input voltage Vin(V)
0
Output volt age Vo( V)
3
Disable voltage Vdis (V)
0.5 1.5
122.5
15.0
12.5
10.0
7.5
5.0
2.5
0
12.04
12.02
12.00
-25
Output voltage Vo(V)
TEMPERATURE Tj(oC)
75 125
02550 100
11.96
11.94
11.92
11.98
10
8
6
4
2
0
Quiescent current Iq(mA)
Junction temperature Tj(
o
C)
75 125
02550 100
-25
-25 0 25 50 75 100 125
0.30
0.35
0.40
0.45
0.50
0.55
0.60
0.65
0.70
2.0A
Drop out voltage Vdrop [V]
Junction Tem p Tj [
!
!!
!
]
Figure 1. Output Voltage vs. Input Voltage Figure 2. Quiescent Current vs. Input Voltage
Figure 4. Output Vo ltage vs. Temperature(Tj)
Figure 3. O utput Voltage vs. Disable Voltage
Figure 5. Quiescent Current vs. Temperature(Tj) Figure 6. Dropout Voltage vs.Junction Temperature
KA278RXXC-SERIES
13
Typical Performance Characteristics
(Continued)
-25
Power dissipation P
D
(W)
TEMPERATURE Tj(
o
C)
75 125
02550 100
15
10
5
20
0
Output Current(A)
Relative output voltage(%)
3.0 5.0
01.02.0 4.0
80
60
20
100
0
40
6.0
Output Current(A)
Relative output voltage(%)
3.0 5.0
01.02.0 4.0
80
60
20
100
0
40
6.0
Relative output voltage(%)
3.0 5.0
01.02.0 4.0
80
60
20
100
0
40
6.0
0123456
3.50
3.75
4.00
4.25
4.50
4.75
Output peak current Iop (A)
Input-output differential voltage Vin-Vo (V)
Figure 7. P ower Di ssipation vs. Tempera ture( Tj) Figure 8. Overc urren t Protection Characteristics
(Typical Value)
0123456
3.50
3.75
4.00
4.25
4.50
4.75
Output peak current Iop (A)
Input-output differential voltage Vin-Vo (V)
Figure 9. Output Peak Cur renr t vs.
Input-Output Differential Voltage
KA278RXXC-SERIES
14
Typical Performance Characteristics
(Continued)
KA278RA05C
51015
Input voltage Vin (V )
6
5
4
3
2
1
7
00
Output voltage Vo(V)
RL=
RL=2.5Ω
ΩΩ
Ω
8
0 5 10 15 20
0
20
40
60
80
100
120
∞
RL=
Qui es c en t c u rre n t Iq (m A )
Input voltage Vin(V)
5.04
5.02
5.00
5.06
-25
Output volt age Vo(V)
TEMPERATURE Tj(
o
C)
75 125
02550 100
4.96
4.94
4.92
4.98
10
8
6
4
2
0
Quiescent current Iq(mA)
Junction temperature Tj(
o
C )
75 125
02550 100
-25
Figure 1. Output Voltage vs. Input Voltage Figure 2. Quiescent Current vs. Input Voltage
Figure 3. Output Voltage vs. Temperature(Tj)
Figure 6. Power Dissipation vs. Te mperature(Tj)
Figure 5. Dropout Voltage vs.Junction Temperature
-25 0 25 50 75 100 125
0.30
0.35
0.40
0.45
0.50
0.55
0.60
0.65
0.70
2.0A
Drop out voltage Vdrop [V]
Ju n ction T e m p T j [
!
!!
!
]
* Fixed Mode (Vo=5V) Figure 4. Quiescent Current vs. Temperature(Tj)
-25
Power dissipation P
D
(W)
TEMPERAT UR E T j(
o
C)
75 125
02550 100
15
10
5
20
0
KA278RXXC-SERIES
15
Typical Performance Characteristics
(Continued)
0123456
3.50
3.75
4.00
4.25
4.50
4.75
Output peak current Iop (A)
Input-output differential voltage Vin-Vo (V)
Figure 7. Overcurrent Protection
Characteristics(Typical value) Figure 8. Output Peak Currenrt vs.
Input-Output Differential Voltage
Output Current(A)
Relative out put v oltage(%)
3.0 5.0
01.02.0 4.0
80
60
20
100
0
40
6.0
Output Current(A)
Relative out put v oltage(%)
3.0 5.0
01.02.0 4.0
80
60
20
100
0
40
6.0
KA278RXXC-SERIES
16
Typical Application
KA278R33/05/51/09/12C
Figu re 1. Appli catio n Circ uit
• Ci is required if regulator is locate d at an appreciab le distance from power supply filter.
• Co improves stability and transient response.(Co > 47µF)
KA278RA05
• Ci is required if regulator is locate d at an appreciab le distance from power supply filter.
• Co improves stability and transient response.(C
O
> 47µF)
+
+
12
3
4
Vin
Vdis
Vo
GND
Disable Signal
KA278RA05
2
Vin
1
3
R3
GND
4
Vo
Vadj
R4
Co R
L
Ci
Output
Input
Vo = 1.25 ( 1 + ) R
1
= 1.8kΩ, R
2
= 0.6kΩ
R
1
//R
3
R
2
//R
4
KA278RA05
2
Vin
1
3
R3
GND
4
Vo
Vadj
R4
Co R
L
Ci
Output
Input
KA278RA05
2
Vin
1
3
R3
GND
4
Vo
Vadj
R4
Co R
L
Ci
Output
Input
Vo = 1.25 ( 1 + ) R
1
= 1.8kΩ, R
2
= 0.6kΩ
R
1
//R
3
R
2
//R
4
Vo = 1.25 ( 1 + ) R
1
= 1.8kΩ, R
2
= 0.6kΩ
R
1
//R
3
R
2
//R
4
20
15
10
-50
Variation(%)
50 100 125
-25 0 25 75
0
-5
-10
5
Junction temperature Tj(")
25
20
15
10
-50
Variation(%)
50 100 125
-25 0 25 75
50 100 125
-25 0 25 75
0
-5
-10
5
Junction temperature Tj(")
25
KA278RA05
2
Vin
1
3
GND
4
Vo
Vadj
Co R
L
Ci
Output = 5V
Input
KA278RA05
2
Vin
1
3
GND
4
Vo
Vadj
Co R
L
Ci
Output = 5V
Input
Figure 2. Appl icat ion Ci rcuit (Adjus table Mode)
Figure 3. Intern al Resi stor(R1,R2) Variati o n vs. Temperature(Tj)
Figure 4. Application Circuit (Fixed Mode)
KA278RXXC-SERIES
17
Mechanic al Dime nsions
Package
Dimensions in millimeters
TO-220F-4L
KA278RXXC-SERIES
18
Mechanic al Dime nsions
(Continued)
Package Dimensions in millimeters
TO-220F-4L(Forming)
KA278RXXC-SERIES
19
Mechanic al Dime nsions
(Continued)
Package Dimensions in millimeters
SPEC NO.
DWG. NO.
5 : 1
SCALE
N/A
TOLERANCE
mm
UNIT
D
TO-220F-4L , SHORT LEAD
TITLE
1. THESE DIMENSIONS DO NOT INCLUDE MOLD PROTRUSION
.
2. ( ) IS REFERENCE
3. [ ] IS ASS'Y OUT QUALITY
NOTE
PKG OUTLINE
TO-220F-4L(Short Lead)
KA278RXXC-SERIES
2/18/05 0. 0m 001
Stock#DSxxxxxxxx
2005 Fairchild Semiconductor Corpor ation
LIFE SU PP ORT POL I CY
FAIRCHIL D’S PRODUCT S ARE NOT AUTHORIZED FOR USE AS CRITICA L COMPONE NTS IN LIFE SUPPORT DE VICES
OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR
CORPORA TION. 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
devic e or sy st em who se fail ur e to pe rf orm can be
reasonably expected to cause the fai lure of the life support
device or system, or to affect its safety or effectiveness.
www.fairchildsemi.com
DISCLAIMER
FAIRCHIL D SEMICONDU CTOR RESERVES T HE RIGHT TO MA KE CHANG ES W I T HOUT FURT HER NOTICE TO ANY
PRODUCTS HEREIN TO IM PROVE RELI ABILITY, FUN CTION OR D ES IG N. FAIRCHILD DOES NOT ASSUME ANY
LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER
DOES IT CONVEY A NY L I CENSE UND ER IT S PATENT R IG HT S, NOR THE RIGH TS OF OTHE RS.
Ordering Information
Product Number Package Operating Temperature
KA278R33CTU
TO-220F-4L
-20°C to +80°C
KA278R05CTU
KA278R51CTU
KA278R09CTU
KA278R12CTU
KA278RA05CTU
KA278R33CYDTU
TO-220F-4L(Forming)
KA278R05CYDTU
KA278R09CYDTU
KA278R12CYDTU
KA278RA05CYDTU
KA278R33CTSTU
TO-220F-4L(Short Lead)
KA278R05CTSTU
KA278R12CTSTU
