MC78T05CD2TG [ONSEMI]
IC VREG 5 V FIXED POSITIVE REGULATOR, PSSO2, D2PAK-3, Fixed Positive Single Output Standard Regulator;
| 型号： | MC78T05CD2TG |
| 厂家： | 
ONSEMI |
| 描述： | IC VREG 5 V FIXED POSITIVE REGULATOR, PSSO2, D2PAK-3, Fixed Positive Single Output Standard Regulator 输出元件 调节器 |
| 文件： | 总10页 (文件大小：203K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
MC78T00 Series
3.0 A Positive Voltage
Regulators
This family of fixed voltage regulators are monolithic integrated
circuits capable of driving loads in excess of 3.0 A. These
three−terminal regulators employ internal current limiting, thermal
shutdown, and safe−area compensation. Devices are available with
improved specifications, including a 2% output voltage tolerance, on
AC−suffix 5.0 V, 12 V and 15 V device types.
Although designed primarily as a fixed voltage regulator, these
devices can be used with external components to obtain adjustable
voltages and currents. This series of devices can be used with a
series−pass transistor to supply up to 15 A at the nominal output
voltage.
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3 A
POSITIVE FIXED
VOLTAGE REGULATORS
MARKING
DIAGRAMS
• Output Current in Excess of 3.0 A
• Power Dissipation: 25 W
• No External Components Required
• Output Voltage Offered in 2% and 4% Tolerance*
• Thermal Regulation is Specified
• Internal Thermal Overload Protection
• Internal Short Circuit Current Limiting
• Output Transistor Safe−Area Compensation
• Pb−Free Packages are Available
TO−220
T SUFFIX
CASE 221A
MC
78TxxyzT
AWLYWW
Pin 1. Input
1
2. Ground*
3. Output
2
3
*Heatsink surface is connected to Pin 2.
MC78TXX
Output
C **
Input
C *
in
0.33 mF
O
MC
78TxxyzD2T
AWLYWW
2
D PAK−3
CASE 936
Figure 51. Simplified Application
ꢀA common ground is required between the input and the output voltages. The input voltage
must remain typically 2.2 V above the output voltage even during the low point on the input
ripple voltage.
MC = Specific Device Code
xx = Voltage Option
XX these two digits of the type number indicate voltage.
** C is required if regulator is located an appreciable distance from power supply filter.
in
** (See Applications Information for details.)
y
= “A” letter for precise 2% regulators, not
used for standard 4% regulators.
= temperature range, “B” for wide
temperature range, −40°C to +125°C, “C”
for standard temperature range,
0°C to +125°C.
** C is not needed for stability; however, it does improve transient response.
O
z
A
= Assembly Location
WL= Wafer Lot
= Year
W = Work Week
Y
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 427 of this data sheet.
©
Semiconductor Components Industries, LLC, 2004
418
Publication Order Number:
March, 2004 − Rev. 4
MC78T00/D
MC78T00 Series
MAXIMUM RATINGS (T = +25°C, unless otherwise noted.)
A
Rating
Symbol
Value
Unit
Input Voltage (5.0 V − 12 V)
Input Voltage (15 V)
V
I
35
40
Vdc
Power Dissipation and Thermal Characteristics
Plastic Package (Note 1)
T = +25°C
A
P
D
Internally Limited
Thermal Resistance, Junction−to−Air
R
P
R
q
JC
65
Internally Limited
2.5
q
JA
°C/W
T
C
= +25°C
D
Thermal Resistance, Junction−to−Case
°C/W
°C
Storage Junction Temperature
T
+150
stg
Operating Junction Temperature Range
(MC78T00C, AC)
T
J
0 to +125
°C
Maximum ratings are those values beyond which device damage can occur. Maximum ratings applied to the device are individual stress limit
values (not normal operating conditions) and are not valid simultaneously. If these limits are exceeded, device functional operation is not implied,
damage may occur and reliability may be affected.
1. Although power dissipation is internally limited, specifications apply only for P ≤ P
, P = 25 W.
max max
O
ELECTRICAL CHARACTERISTICS (V = 10 V, I = 3.0 A, 0°C ≤ T ≤ 125°C, P ≤ P
(Note 2), unless otherwise noted.)
in
O
J
O
max
MC78T05AC
MC78T05C
Min
Typ
Max
Min
Typ
Max
Characteristics
Symbol
Unit
Output Voltage
(5.0 mA ≤ I ≤ 3.0 A, T = +25°C)
V
O
Vdc
4.9
4.8
5.0
5.0
5.1
5.2
4.8
4.75
5.0
5.0
5.2
5.25
O
J
(5.0 mA ≤ I ≤ 3.0 A;
O
5.0 mA ≤ I ≤ 2.0 A, 7.3 Vdc ≤ V ≤ 20 Vdc)
O
in
Line Regulation (Note 3)
Reg
−
3.0
25
−
3.0
25
mV
mV
line
(7.2 Vdc ≤ V ≤ 35 Vdc, I = 5.0 mA, T = +25°C;
in
O
J
7.2 Vdc ≤ V ≤ 35 Vdc, I = 1.0 A, T = +25°C;
in
O
J
8.0 Vdc ≤ V ≤ 12 Vdc, I = 3.0 A, T = +25°C;
in
O
J
7.5 Vdc ≤ V ≤ 20 Vdc, I = 1.0 A)
in
O
Load Regulation (Note 3)
Reg
load
(5.0 mA ≤ I ≤ 3.0 A, T = +25°C)
−
−
10
15
30
80
−
−
10
15
30
80
O
J
(5.0 mA ≤ I ≤ 3.0 A)
O
Thermal Regulation
Reg
−
0.001
0.01
−
0.002
0.03
%V /W
therm
O
(Pulse = 10 ms, P = 20 W, T = +25°C)
A
Quiescent Current
I
mA
mA
B
(5.0 mA ≤ I ≤ 3.0 A, T = +25°C)
−
−
3.5
4.0
5.0
6.0
−
−
3.5
4.0
5.0
6.0
O
J
(5.0 mA ≤ I ≤ 3.0 A)
O
Quiescent Current Change
(7.2 Vdc ≤ V ≤ 35 Vdc, I = 5.0 mA, T = +25°C;
DI
−
0.3
1.0
−
0.3
1.0
B
in
O
J
5.0 mA ≤ I ≤ 3.0 A, T = +25°C;
O
J
7.5 Vdc ≤ V ≤ 20 Vdc, I = 1.0 A)
in
O
Ripple Rejection
RR
62
75
−
62
75
−
dB
(8.0 Vdc ≤ V ≤ 18 Vdc, f = 120 Hz,
in
I
O
= 2.0 A, T = 25°C)
J
Dropout Voltage (I = 3.0 A, T = +25°C)
V −V
O
−
−
2.2
10
2.5
−
−
2.2
10
2.5
Vdc
O
J
in
Output Noise Voltage
V
n
−
−
mV/V
O
(10 Hz ≤ f ≤ 100 kHz, T = +25°C)
J
Output Resistance (f = 1.0 kHz)
R
O
−
2.0
−
−
20
−
mW
2. Although power dissipation is internally limited, specifications apply only for P ≤ P
, P = 25 W.
max max
O
3. Line and load regulation are specified at constant junction temperature. Changes in V due to heating effects must be taken into account
O
separately.
Pulse testing with low duty cycle is used.
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419
MC78T00 Series
ELECTRICAL CHARACTERISTICS (V = 10 V, I = 3.0 A, 0°C ≤ T ≤ 125°C, P ≤ P
(Note 2), unless otherwise noted.)
in
O
J
O
max
MC78T05AC
MC78T05C
Min
Typ
Max
Min
Typ
Max
Characteristics
Short Circuit Current Limit
(V = 35 Vdc, T = +25°C)
Symbol
Unit
I
−
1.5
−
−
1.5
−
A
SC
in
J
Peak Output Current (T = +25°C)
I
−
−
5.0
0.2
−
−
−
−
5.0
0.2
−
−
A
J
max
Average Temperature Coefficient of Output Voltage
(I = 5.0 mA)
TCV
mV/°C
O
O
2. Although power dissipation is internally limited, specifications apply only for P ≤ P
, P = 25 W.
max max
O
3. Line and load regulation are specified at constant junction temperature. Changes in V due to heating effects must be taken into account
O
separately.
Pulse testing with low duty cycle is used.
ELECTRICAL CHARACTERISTICS (V = 13 V, I = 3.0 A, 0°C ≤ T ≤ 125°C, P ≤ P
(Note 4), unless otherwise noted.)
in
O
J
O
max
MC78T08C
Min
Typ
Max
Characteristics
Symbol
Unit
Output Voltage
(5.0 mA ≤ I ≤ 3.0 A, T = +25°C)
V
O
Vdc
7.7
7.6
8.0
8.0
8.3
8.4
O
J
(5.0 mA ≤ I ≤ 3.0 A;
O
5.0 mA ≤ I ≤ 2.0 A, 10.4 Vdc ≤ V ≤ 23 Vdc)
O
in
Line Regulation (Note 5)
Reg
−
4.0
35
mV
mV
line
(10.3 Vdc ≤ V ≤ 35 Vdc, I = 5.0 mA, T = +25°C
in
O
J
10.3 Vdc ≤ V ≤ 35 Vdc, I = 1.0 A, T = +25°C
in
O
J
11 Vdc ≤ V ≤ 17 Vdc, I = 3.0 A, T = +25°C
in
O
J
10.7 Vdc ≤ V ≤ 23 Vdc, I = 1.0 A)
in
O
Load Regulation (Note 5)
Reg
load
(5.0 mA ≤ I ≤ 3.0 A, T = +25°C)
−
−
10
15
30
80
O
J
(5.0 mA ≤ I ≤ 3.0 A)
O
Thermal Regulation
Reg
−
0.002
0.03
%V /W
therm
O
(Pulse = 10 ms, P = 20 W, T = +25°C)
A
Quiescent Current
I
mA
mA
B
(5.0 mA ≤ I ≤ 3.0 A, T = +25°C)
−
−
3.5
4.0
5.0
6.0
O
J
(5.0 mA ≤ I ≤ 3.0 A)
O
Quiescent Current Change
(10.3 Vdc ≤ V ≤ 35 Vdc, I = 5.0 mA, T = +25°C;
DI
−
0.3
1.0
B
in
O
J
5.0 mA ≤ I ≤ 3.0 A, T = +25°C;
O
J
10.7 Vdc ≤ V ≤ 23 Vdc, I = 1.0 A)
in
O
Ripple Rejection
RR
60
71
−
dB
(11 Vdc ≤ V ≤ 21 Vdc, f = 120 Hz, I = 2.0 A, T = 25°C)
in
O
J
Dropout Voltage (I = 3.0 A, T = +25°C)
V −V
O
−
−
2.2
10
2.5
Vdc
O
J
in
Output Noise Voltage
V
n
−
mV/V
O
(10 Hz ≤ f ≤ 100 kHz, T = +25°C)
J
Output Resistance (f = 1.0 kHz)
Short Circuit Current Limit
R
−
−
2.0
1.5
−
−
mW
O
I
A
SC
(V = 35 Vdc, T = +25°C)
in
J
Peak Output Current (T = +25°C)
I
−
−
5.0
0.3
−
−
A
J
max
Average Temperature Coefficient of Output Voltage (I = 5.0 mA)
TCV
mV/°C
O
O
4. Although power dissipation is internally limited, specifications apply only for P ≤ P
, P = 25 W.
O
O
max max
5. Line and load regulation are specified at constant junction temperature. Changes in V due to heating effects must be taken into account
separately.
Pulse testing with low duty cycle is used.
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420
MC78T00 Series
ELECTRICAL CHARACTERISTICS (V = 17 V, I = 3.0 A, 0°C ≤ T ≤ 125°C, P ≤ P
(Note 6), unless otherwise noted.)
in
O
J
O
max
MC78T12AC
Typ
MC78T12C
Min
Max
Min
Typ
Max
Characteristics
Symbol
Unit
Output Voltage
(5.0 mA ≤ I ≤ 3.0 A, T = +25°C)
V
O
Vdc
11.75
11.5
12
12
12.25
12.5
11.5
11.4
12
12
12.5
12.6
O
J
(5.0 mA ≤ I ≤ 3.0 A,
O
5.0 mA ≤ I ≤ 2.0 A, 14.5 Vdc ≤ V ≤ 27 Vdc)
O
in
Line Regulation (Note 7)
Reg
−
6.0
45
−
6.0
45
mV
mV
line
(14.5 Vdc ≤ V ≤ 35 Vdc, I = 5.0 mA, T = +25°C;
in
O
J
14.5 Vdc ≤ V ≤ 35 Vdc, I = 1.0 A, T = +25°C;
in
O
J
16 Vdc ≤ V ≤ 22 Vdc, I = 3.0 A, T = +25°C;
in
O
J
14.9 Vdc ≤ V ≤ 27 Vdc, I = 1.0 A)
in
O
Load Regulation (Note 7)
Reg
load
(5.0 mA ≤ I ≤ 3.0 A, T = +25°C)
−
−
10
15
30
80
−
−
10
15
30
80
O
J
(5.0 mA ≤ I ≤ 3.0 A)
O
Thermal Regulation
Reg
−
0.001
0.01
−
0.002
0.03
%V /W
therm
O
(Pulse = 10 ms, P = 20 W, T = +25°C)
A
Quiescent Current
I
mA
mA
B
(5.0 mA ≤ I ≤ 3.0 A, T = +25°C)
−
−
3.5
4.0
5.0
6.0
−
−
3.5
4.0
5.0
6.0
O
J
(5.0 mA ≤ I ≤ 3.0 A)
O
Quiescent Current Change
(14.5 Vdc ≤ V ≤ 35 Vdc, I = 5.0 mA, T = +25°C;
DI
−
0.3
1.0
−
0.3
1.0
B
in
O
J
5.0 mA ≤ I ≤ 3.0 A, T = +25°C;
O
J
14.9 Vdc ≤ V ≤ 27 Vdc, I = 1.0 A)
in
O
Ripple Rejection
RR
57
67
−
57
67
−
dB
(15 Vdc ≤ V ≤ 25 Vdc, f = 120 Hz,
in
I
O
= 2.0 A, T = 25°C)
J
Dropout Voltage (I = 3.0 A, T = +25°C)
V
in
− V
O
−
−
2.2
10
2.5
−
−
2.2
10
2.5
Vdc
O
J
Output Noise Voltage
V
n
−
−
mV/V
O
(10 Hz ≤ f ≤ 100 kHz, T = +25°C)
J
Output Resistance (f = 1.0 kHz)
Short Circuit Current Limit
R
−
−
2.0
1.5
−
−
−
−
20
−
−
mW
O
I
1.5
A
SC
(V = 35 Vdc, T = +25°C)
in
J
Peak Output Current (T = +25°C)
I
−
−
5.0
0.5
−
−
−
−
5.0
0.5
−
−
A
J
max
Average Temperature Coefficient
TCV
mV/°C
O
of Output Voltage (I = 5.0 mA)
O
6. Although power dissipation is internally limited, specifications apply only for P ≤ P
, P
O
= 25 W.
O
max max
7. Line and load regulation are specified at constant junction temperature. Changes in V due to heating effects must be taken into account
separately.
Pulse testing with low duty cycle is used.
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421
MC78T00 Series
ELECTRICAL CHARACTERISTICS (V = 20 V, I = 3.0 A, 0°C ≤ T ≤ 125°C, P ≤ P
(Note 8), unless otherwise noted.)
in
O
J
O
max
MC78T15AC
MC78T15C
Min
Typ
Max
Min
Typ
Max
Characteristics
Symbol
Unit
Output Voltage
(5.0 mA ≤ I ≤ 3.0 A, T = +25°C)
V
O
Vdc
14.7
14.4
15
15
15.3
15.6
14.4
14.25
15
15
15.6
15.75
O
J
(5.0 mA ≤ I ≤ 3.0 A;
O
5.0 mA ≤ I ≤ 2.0 A, 17.5 Vdc ≤ V ≤ 30 Vdc)
O
in
Line Regulation (Note 9)
Reg
−
7.5
55
−
7.5
55
mV
mV
line
(17.6 Vdc ≤ V ≤ 40 Vdc, I = 5.0 mA, T = +25°C;
in
O
J
17.6 Vdc ≤ V ≤ 40 Vdc, I = 1.0 A, T = +25°C;
in
O
J
20 Vdc ≤ V ≤ 26 Vdc, I = 3.0 A, T = +25°C;
in
O
J
18 Vdc ≤ V ≤ 30 Vdc, I = 1.0 A)
in
O
Load Regulation (Note 9)
Reg
load
(5.0 mA ≤ I ≤ 3.0 A, T = +25°C)
−
−
10
15
30
80
−
−
10
15
30
80
O
J
(5.0 mA ≤ I ≤ 3.0 A)
O
Thermal Regulation
Reg
−
0.001
0.01
−
0.002
0.03
%V /W
therm
O
(Pulse = 10 ms, P = 20 W, T = +25°C)
A
Quiescent Current
I
mA
mA
B
(5.0 mA ≤ I ≤ 3.0 A, T = +25°C)
−
−
3.5
4.0
5.0
6.0
−
−
3.5
4.0
5.0
6.0
O
J
(5.0 mA ≤ I ≤ 3.0 A)
O
Quiescent Current Change
(17.6 Vdc ≤ V ≤ 40 Vdc, I = 5.0 mA, T = +25°C;
DI
−
0.3
1.0
−
0.3
1.0
B
in
O
J
5.0 mA ≤ I ≤ 3.0 A, T = +25°C;
O
J
18 Vdc ≤ V ≤ 30 Vdc, I = 1.0 A)
in
O
Ripple Rejection
RR
55
65
−
55
65
−
dB
(18.5 Vdc ≤ V ≤ 28.5 Vdc, f = 120 Hz,
in
I
O
= 2.0 A, T = 25°C)
J
Dropout Voltage (I = 3.0 A, T = +25°C)
V −V
O
−
−
2.2
10
2.5
−
−
2.2
10
2.5
Vdc
O
J
in
Output Noise Voltage
V
n
−
−
mV/V
O
(10 Hz ≤ f ≤ 100 kHz, T = +25°C)
J
Output Resistance (f = 1.0 kHz)
Short Circuit Current Limit
R
−
−
2.0
1.0
−
−
−
−
20
−
−
mW
O
I
1.0
A
SC
(V = 40 Vdc, T = +25°C)
in
J
Peak Output Current (T = +25°C)
I
−
−
5.0
0.6
−
−
−
−
5.0
0.6
−
−
A
J
max
Average Temperature Coefficient of Output Voltage
(I = 5.0 mA)
TCV
mV/°C
O
O
8. Although power dissipation is internally limited, specifications apply only for P ≤ P
, P
O
= 25 W.
O
max max
9. Line and load regulation are specified at constant junction temperature. Changes in V due to heating effects must be taken into account
separately.
Pulse testing with low duty cycle is used.
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MC78T00 Series
VOLTAGE REGULATOR PERFORMANCE
The performance of a voltage regulator is specified by its
can be caused by a change in either the input voltage or the
load current. Thermal regulation is a function of IC layout
and die attach techniques, and usually occurs within 10 ms
of a change in power dissipation. After 10 ms, additional
changes in the output voltage are due to the temperature
coefficient of the device.
Figure 1 shows the line and thermal regulation response
of a typical MC78T05AC to a 20 W input pulse. The
variation of the output voltage due to line regulation is
labeled ➀ and the thermal regulation component is labeled
➀. Figure 2 shows the load and thermal regulation response
of a typical MC78T05AC to a 20 W load pulse. The output
voltage variation due to load regulation is labeled ➀ and the
thermal regulation component is labeled ➀.
immunity to changes in load, input voltage, power
dissipation, and temperature. Line and load regulation are
tested with a pulse of short duration (< 100 ms) and are
strictly a function of electrical gain. However, pulse widths
of longer duration (> 1.0 ms) are sufficient to affect
temperature gradients across the die. These temperature
gradients can cause a change in the output voltage, in
addition to changes caused by line and load regulation.
Longer pulse widths and thermal gradients make it
desirable to specify thermal regulation.
Thermal regulation is defined as the change in output
voltage caused by a change in dissipated power for a
specified time, and is expressed as a percentage output
voltage change per watt. The change in dissipated power
2
2
2
1
2
1
18
2.0
8.0
0
t, TIME (2.0 ms/DIV)
t, TIME (2.0 ms/DIV)
V
= 5.0 V
= 8.0 V → 18 V → 8.0 V
= 2.0 A
V
= 5.0 V
out
out
1
2
= Reg = 2.4 mV
line
1 = Reg = 4.4 mV
line
V
I
V = 15
in
in
2
= Reg
= 0.0015%V /W
O
I
= 0 A → 2.0 A → 0 A
= Reg
= 0.0015%V /W
therm O
out
therm
out
Figure 1. MC78T05AC Line and Thermal Regulation
Figure 2. MC78T05AC Load and Thermal Regulation
Input
1.0k
1.0k
Q2
Q1
Q21
210
Q20
6.7V
16k
Q22
100
200
Q24
Q25
Q9
Q26
13
1.0k
Q19
Q8
300
Q3
Q27
0.12
3.0k
10pF
Q23
3.6k
6.4k
Q4
5.6k
300
Q16
Q5
Q10
200
50
Output
520
40
pF
Q12
2.6k
8.0−15ꢁV
O
6.0k
Q17
Q18
5.0 V
3.9k
O
2.0k
Q11
Q6
Q7
Q13
6.0k
Q15
2.8k
Gnd
Q14
Figure 3. Representative Schematic Diagram
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423
MC78T00 Series
0
1.02
10
V
− V = 10 V
out
= 100 mA
1
in
10−
I
out
V
= 5.0 V
= 7.5 V
= 1.0 A
= 0
out
V
I
in
2
out
10−
1.0
C
O
T = 25°C
J
3
10−
4
.98
10−
−90
−50
−10
30
70
110
150
190
1.0
10
100 1.0 k
10 k 100 k 1.0 M 10 M 100 M
T , JUNCTION TEMPERATURE (°C)
J
f, FREQUENCY (Hz)
Figure 4. Temperature Stability
Figure 5. Output Impedance
100
80
100
80
60
40
20
I
= 50 mA
out
I
= 1.5 A
out
V
V
C
= 5.0 V
out
V
= 5.0 V
out
= 10 V
= 0
60
= 10 V
= 0
f = 120 Hz
in
V
in
O
C
O
T = 25°C
J
T = 25°C
J
40
30
0.01
0.1
1.0
10
1.0
10
100 1.0 k 10 k 100 k 1.0 M 10 M 100 M
f, FREQUENCY (Hz)
I
, OUTPUT CURRENT (A)
out
Figure 6. Ripple Rejection versus Frequency
Figure 7. Ripple Rejection versus
Output Current
4.0
3.0
2.0
5.0
4.0
3.0
2.0
1.0
0
T = 0°C
J
T = 25°C
J
T = 0°C
J
T = 125°C
J
T = 25°C
J
T = 125°C
J
1.0
0
T = 0°C
T = 25°C
T = 125°C
J
V −V = 5.0 V
in out
J
J
0
10
20
V , INPUT VOLTAGE (Vdc)
30
40
0.01
0.1
, OUTPUT CURRENT (A)
out
1.0
10
I
in
Figure 8. Quiescent Current versus
Input Voltage
Figure 9. Quiescent Current versus
Output Current
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424
MC78T00 Series
2.5
2.0
1.5
1.0
0.5
8.0
I
= 3.0 A
out
6.0
4.0
2.0
0
I
= 1.0 A
out
I
= 0.5 A
out
T = 0°C
J
DV = 50 mV
O
T = 25°C
J
T = 125°C
J
−90
−50
−10
30
70
110
150
190
0
10
20
30
40
T , JUNCTION TEMPERATURE (°C)
J
V −V , INPUT−OUTPUT VOLTAGE (Vdc)
in O
Figure 10. Dropout Voltage
Figure 11. Peak Output Current
0.8
0.6
0.4
0.2
0
0.3
0.2
0.1
V
= 5.0 V
out
= 150 mA
= 0
V
C
= 10 V
= 0
in
I
out
O
C
T = 25°C
J
O
T = 25°C
J
0
−0.1
−0.2
−0.3
−0.2
−0.4
−0.6
1.5
1.0
1.0
0.5
0
0.5
0
0
10
20
t, TIME (ms)
30
40
0
10
20
30
40
t, TIME (ms)
Figure 12. Line Transient Response
Figure 13. Load Transient Response
40
Maximum Ambient
Temperature
q
of Heatsinks
SA
30
20
1.3°C/W
2.4°C/W
3.3°C/W
Infinite
Heatsink
10
0
6.3°C/W
10.5°C
25
50
75
100
125
T , AMBIENT TEMPERATURE (°C)
A
Figure 14. Maximum Average Power
Dissipation for MC78T00CT, ACT
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MC78T00 Series
APPLICATIONS INFORMATION
Design Considerations
regulator is connected to the power supply filter with long
wire lengths, or if the output load capacitance is large. An
input bypass capacitor should be selected to provide good
high frequency characteristics to insure stable operation
under all load conditions. A 0.33 mF or larger tantalum,
mylar, or other capacitor having low internal impedance at
high frequencies should be chosen. The bypass capacitor
should be mounted with the shortest possible leads directly
across the regulator’s input terminals. Normally good
construction techniques should be used to minimize ground
loops and lead resistance drops since the regulator has no
external sense lead.
The MC78T00 Series of fixed voltage regulators are
designed with Thermal Overload Protection that shuts
down the circuit when subjected to an excessive power
overload condition, Internal Short Circuit Protection that
limits the maximum current the circuit will pass, and
Output Transistor Safe−Area Compensation that reduces
the output short circuit current as the voltage across the pass
transistor is increased.
In many low current applications, compensation
capacitors are not required. However, it is recommended
that the regulator input be bypassed with a capacitor if the
Output
MC78T05
MC78T05
Input
Input
R
0.33mF
Constant
Current to
Grounded Load
7
4
2
3
−
+
I
O
0.33mF
0.1mF
6
The MC78T05 regulator can also be used as a current source
when connected as above. In order to minimize dissipation the
MC78T05 is chosen in this application. Resistor R determines
the current as follows:
10k
1.0k
MC1741
5.0 V
I
0
+
) I
B
R
V , 8.0 V to 20 V
O
V
in
− V ≥ 2.5 V
O
DI ^ 0.7 mA over line, load and Temperature changes
B
I
^ 3.5 mA
The addition of an operational amplifier allows adjustment to higher or
intermediate values while retaining regulation characteristics. The
minimum voltage obtainable with this arrangement is 3.0 V greater
than the regulator voltage.
B
For example, a 2.0 A current source would require R to be a 2.5 W,
10ꢁW resistor and the output voltage compliance would be the input
voltage less 7.0 V.
Figure 15. Current Regulator
Figure 16. Adjustable Output Regulator
2N4398
or Equiv.
Input
R
sc
2N4398 or Equiv
MJ2955
or Equiv.
R
MC78TXX
Output
R
MC78TXX
Output
1.0mF
1.0mF
XX = 2 digits of type number indicating voltage.
0.1mF
XX = 2 digits of type number indicating voltage.
The MC78T00 series can be current boosted with a PNP transistor. The
2N4398 provides current to 15 A. Resistor R in conjunction with the V
The circuit of Figure 17 can be modified to provide supply protection
against short circuits by adding a short circuit sense resistor, R , and
BE
SC
of the PNP determines when the pass transistor begins conducting; this
circuit is not short circuit proof. Input−output differential voltage
minimum is increased by the V of the pass transistor.
an additional PNP transistor. The current sensing PNP must be able to
handle the short circuit current of the three−terminal regulator.
Therefore, an eight−ampere power transistor is specified.
BE
Figure 17. Current Boost Regulator
Figure 18. Current Boost With
Short Circuit Protection
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426
MC78T00 Series
ORDERING INFORMATION
Nominal
Output Voltage
Operating
Temperature Range
†
Device
MC78T05ABT
MC78T05ACT
MC78T05ACTG
V
O
Tol.
Package
TO−220
TO−220
Shipping
2%*
2%*
2%*
T = −40°C TO +125°C
50 Units / Rail
50 Units / Rail
50 Units / Rail
J
T = 0°C TO +125°C
J
T = 0°C TO +125°C
TO−220
(Pb−Free)
J
MC78T05BT
4%
4%
T = −40°C TO +125°C
TO−220
50 Units / Rail
J
MC78T05BTG
T = −40°C TO +125°C
J
TO−220
(Pb−Free)
50 Units / Tubes
5.0 V
2
MC78T05CD2T
MC78T05CD2TR4
MC78T05CT
4%
4%
4%
4%
T = 0°C TO +125°C
D PAK−3
50 Units / Rail
800 / Tape & Reel
50 Units / Rail
J
2
T = 0°C TO +125°C
J
D PAK−3
T = 0°C TO +125°C
J
TO−220
MC78T05CTG
T = 0°C TO +125°C
J
TO−220
(Pb−Free)
50 Units / Rail
MC78T08CT
MC78T12ACT
MC78T12BT
MC78T12CT
MC78T15ABT
MC78T15ACT
MC78T15CT
4%
2%*
4%
8.0 V
12 V
T = 0°C TO +125°C
TO−220
TO−220
TO−220
TO−220
TO−220
TO−220
TO−220
50 Units / Rail
50 Units / Rail
50 Units / Rail
50 Units / Rail
50 Units / Rail
50 Units / Rail
50 Units / Rail
J
T = 0°C TO +125°C
J
T = −40°C TO +125°C
J
4%
T = 0°C TO +125°C
J
2%*
2%*
4%
T = −40°C TO +125°C
J
T = 0°C TO +125°C
J
15 V
T = 0°C TO +125°C
J
NOTE: Automotive temperature range selections are available with special test conditions and additional tests. Contact your local
ON Semiconductor sales office for information.
†For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging
Specifications Brochure, BRD8011/D.
*2% regulators available in 5.0 V, 12 V and 15 V devices.
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