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MC78TXX
3-Terminal 3A Positive Voltage Regulator
Features
•
•
•
•
•
•
•
•
Output Current in Excess of 3.0A
Output Transistor Safe Operating Area Compensation
Power Dissipation :25W
Internal Short Circuit Current Limiting
Internal Thermal Overload Protection
Output Voltage Offered in 4% Tolerance
No External Components Required
Output Voltage of 5,12 and 15V
Description
This family of fixed voltage regulators are monolithic
integrated circuit capable of driving loads in excess of 3.0 A.
TO-220
GND
1
1.Input 2. GND 3. Output
Internal Block Diagram
INPUT
1
CURRENT
GENERATOR
SERIES
PASS
ELEMENT
OUTPUT
3
SOA
PROTECTION
STARTING
CIRCUIT
REFERENCE
VOLTAGE
ERROR
AMPLIFIER
THERMAL
PROTECTION
GND
2
Rev. 1.0.1
©2002 Fairchild Semiconductor Corporation
MC78TXX
Absolute Maximum Ratings
Parameter
Input Voltage (for V
O
= 5V to 12V)
(for V
O
= 15V)
Power Dissipation
Thermal Resistance, Junction to Air (Note1, 2)
Ta = +25°C
Thermal Resistance, Junction to Case (Note1)
Tc = +25°C
Operating Junction Temperature Range
Storage Temperature Range
Note:
1. Thermal resistance test board
Size: 76.2mm * 114.3mm * 1.6mm(1S0P)
JEDEC standard: JESD51-3, JESD51-7
2. Assume no ambient airflow.
Symbol
V
I
PD
RθJA
RθJC
T
J
T
STG
Value
35
40
Internally limited
65
2.5
0 ~ +125
-65 ~ +150
Unit
V
V
°C/W
°C/W
°C
°C
Electrical Characteristics(MC78T05)
(V
I
= 10V, I
O
= 3.0 A, 0°C
≤
T
J
≤
+125°C, Po
≤
P
MAX
(Note3), unless otherwise specified. )
Parameter
Output Voltage
Symbol
Vo
Conditions
5mA
≤
Io
≤
3.0A , T
J
= +25°C
7.3V
≤
VI
≤
20V, 5mA
≤
Io
≤
2.0A
7.2V
≤
VI
≤
35V , Io=5mA, T
J
=+25°C
7.2V
≤
VI
≤
35V , Io=1.0A, T
J
= +25°C
7.5V
≤
VI
≤
20V, Io =2.0A, T
J
= +25°C
8.0V
≤
VI
≤
12V, Io =3.0A, T
J
= +25°C
5mA
≤
Io
≤
3.0A , T
J
= +25°C
5mA
≤
Io
≤
3.0A
Pulse =10ms, P = 20W
T
A
= +25°C
5mA
≤
Io
≤
3.0A , T
J
= +25°C
5mA
≤
Io
≤
3.0A
7.2V
≤
VI
≤
35V, Io = 5mA
T
J
= +25°C ;
7.5V
≤
VI
≤
20V, Io =2.0A ;
5mA
≤
Io
≤
3.0A, T
J
= +25°C
f = 120Hz, 8V
≤
V
I
≤
18V, I
o
=
2.0A
T
J
= +25°C
Io = 3A ,T
J
= +25°C
T
A
= +25°C, 10Hz
≤
f
≤
100kHz
T
A
= +25°C
f = 1.0kHz
VI = 35V, T
J
=+25°C
Io = 5.0mA
Min.
4.8
4.75
-
Typ.
5.0
5.0
3.0
10
15
0.002
3.5
4.0
0.1
Max.
5.2
5.25
25
30
80
0.03
5.0
6.0
0.8
Unit
V
Line Regulation (Note4)
∆V
O
mV
mV
mV
%Vo/W
mA
mA
mA
Load Regulation (Note4)
Thermal Regulation
Quiescent Current
∆V
O
REG
T
I
Q
-
-
-
Quiescent Current Change
∆I
Q
-
Ripple Rejection
Dropout Voltage
Output Noise Voltage
Peak Output Current
Output Resistance
Short Circuit Current Limit
RR
V
D
V
N
I
PK
Ro
Isc
-
-
-
-
-
-
-
75
2.2
10
5.0
2.0
1.5
0.2
-
2.5
-
-
-
2.5
-
dB
V
µV/Vo
A
mΩ
A
mV/°C
Average Temperature
∆V
O
/∆T
Coefficient of Output Voltage
Note:
3. Although power dissipation is internally limited, specifications apply only for P
O
≤
Pmax, Pmax = 25W
4. Load and line regulation are specified at constant junction temperature. Change in Vo due heating effects must be taken into
account separately. Pulse testing with low duty is used.
2
MC78TXX
Electrical Characteristics(MC78T12)
(Continued)
(V
I
= 19V, I
O
= 3.0 A, 0°C
≤
T
J
≤
+125°C, Po
≤
P
MAX
(Note1), unless otherwise specified. )
Parameter
Output Voltage
Symbol
Vo
Conditions
5mA
≤
Io
≤
3.0A , T
J
=+25°C
14.5V
≤
VI
≤
27V, 5mA
≤
Io
≤
2.0A
14.5V
≤
VI
≤
35V, Io=5mA, T
J
=+25°C
14.5V
≤
VI
≤
35V, Io=1.0A, T
J
=+25°C
14.9V
≤
VI
≤
28V, Io =2.0A, T
J
=+25°C
16V
≤
VI
≤
22V, Io =3.0A, T
J
=+25°C
5mA
≤
Io
≤
3.0A, T
J
=+25°C
5mA
≤
Io
≤
3.0A
Pulse =10ms, P = 20W
TA = +25°C
5mA
≤
Io
≤
3.0A, T
J
=+25°C
5mA
≤
Io
≤
3.0A
14.5V
≤
VI
≤
35V, Io = 5mA
T
J
=+25°C ;
14.9V
≤
VI
≤
27V, Io =2.0A ;
5mA
≤
Io
≤
3.0A, T
J
=+25°C
f = 120Hz, 15V
≤
V
I
≤
25V, Io
=
2.0A
T
J
=+25°C
Io = 3A,T
J
=+25°C
T
A
=+25°C, 10Hz
≤
f
≤
100kHz
T
A
=+25°C
f = 1.0kHz
VI = 35V, T
J
=+25°C
Io = 5.0mA
Min.
11.5
11.4
-
Typ.
12
12
6.0
10
15
0.002
3.5
4.0
0.1
Max.
12.5
12.8
45
30
80
0.03
5.0
6.0
0.8
Unit
V
Line Regulation (Note2)
∆V
O
mV
mV
mV
%Vo/W
mA
mA
mA
Load Regulation (Note2)
Thermal Regulation
Quiescent Current
∆V
O
REG
T
I
Q
∆I
Q
-
-
-
Quiescent Current Change
-
Ripple Rejection
Dropout Voltage
Output Noise Voltage
Peak Output Current
Output Resistance
Short Circuit Current Limit
RR
V
D
V
N
I
PK
Ro
Isc
-
-
-
-
-
-
-
67
2.2
10
5.0
2.0
1.5
0.5
-
2.5
-
-
-
2.5
-
dB
V
µV/Vo
A
mΩ
A
mV/°C
Average Temperature
∆V
O
/∆T
Coefficient of Output Voltage
Note:
1. Although power dissipation is internally limited, specifications apply only for P
O
≤
Pmax, Pmax = 25W
2. Load and line regulation are specified at constant junction temperature. Change in Vo due heating effects must be taken into
account separately. Pulse testing with low duty is used. ( P
MAX
= 25W)
3
MC78TXX
Electrical Characteristics(MC78T15)
(Continued)
(V
I
= 23V, I
O
= 3.0 A, 0°C
≤
T
J
≤
+125°C, Po
≤
P
MAX
(Note1), unless otherwise specified. )
Parameter
Output Voltage
Symbol
Vo
Conditions
5mA
≤
Io
≤
3.0A, T
J
=+25°C
17.5V
≤
VI
≤
30V, 5mA
≤
Io
≤
2.0A
17.6V
≤
VI
≤
40V, Io=5mA, T
J
=+25°C
17.6V
≤
VI
≤
40V, Io=1.0A, T
J
=+25°C
18V
≤
VI
≤
30V, Io =2.0A, T
J
=+25°C
20V
≤
VI
≤
26V, Io =3.0A, T
J
=+25°C
5mA
≤
Io
≤
3.0A, T
J
=+25°C
5mA
≤
Io
≤
3.0A
Pulse =10ms, P = 20W
TA = +25°C
5mA
≤
Io
≤
3.0A, T
J
=+25°C
5mA
≤
Io
≤
3.0A
17.6V
≤
VI
≤
40V, Io = 5mA
T
J
=+25°C ;
18V
≤
VI
≤
30V, Io =2.0A ;
5mA
≤
Io
≤
3.0A, T
J
=+25°C
f = 120Hz, 18.5V
≤
V
I
≤
28.5V, Io
=
2.0A
T
J
=+25°C
Io = 3A ,T
J
= +25°C
T
A
= +25°C, 10Hz
≤
f
≤
100kHz
T
A
= +25°C
f = 1.0kHz
VI = 40V, T
J
= +25°C
Io = 5.0mA
Min.
14.4
14.25
-
Typ.
15
15
7.5
10
15
0.002
3.5
4.0
0.1
Max.
15.6
15.75
55
30
80
0.03
5.0
6.0
0.8
Unit
V
Line Regulation (Note2)
∆V
O
mV
mV
mV
%Vo/W
mA
mA
mA
Load Regulation (Note2)
Thermal Regulation
Quiescent Current
∆V
O
REG
T
I
Q
∆I
Q
-
-
-
Quiescent Current Change
-
Ripple Rejection
Dropout Voltage
Output Noise Voltage
Peak Output Current
Output Resistance
Short Circuit Current Limit
RR
V
D
V
N
I
PK
Ro
Isc
-
-
-
-
-
-
-
65
2.2
10
5.0
2.0
1.0
0.5
-
2.5
-
-
-
2.0
-
dB
V
µV/Vo
A
mΩ
A
mV/°C
Average Temperature
∆V
O
/∆T
Coefficient of Output Voltage
Note:
1. Although power dissipation is internally limited, specifications apply only for P
O
≤
Pmax, Pmax = 25W
2. Load and line regulation are specified at constant junction temperature. Change in Vo due heating effects must be taken into
account separately. Pulse testing with low duty is used. ( P
MAX
= 25W)
4
MC78TXX
Typical Application
INPUT
1
KA78TXX
MC78TXX
2
3
OUTPUT
0.33
µF
0. 1
µF
Note:
1. To specify an output voltage, substitute voltage value for “XX”.
2. Bypass Capacitors are recommend for optimum stability and transient response and should be located as close as possible
to the regulator
5
Embedded System
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