This is information on a product in full production.
March 2014 DocID2148 Rev 8 1/35
L78S
2 A positive voltage regulator IC
Datasheet
-
production data
Features
•Output current up to 2 A
•Output voltages of 5; 7.5; 9; 10; 12; 15; 18; 24 V
•Thermal protection
•Short circuit protection
•Output transition SOA protection
Description
The L78S series of three-terminal positive
regulators is available in TO-220 package and
several fixed output voltages, making it useful in a
wide range of applications. These regulators can
provide local on-card regulation, eliminating the
distributi on pr obl ems ass ocia ted with sing le poi nt
regulation. Each type embeds internal current
limiting, thermal shut-down and safe area
protection, making it essentially indestructible. If
adequate heat sinking is provided, they can
deliver over 2 A output current. Although
designed primarily as fixed voltage regulators,
these devices can be used with external
components to obtain adjustable voltages and
currents.
TO-220
Table 1. Device summary
Par t numb ers TO-220 packages Out put voltag e
Dual gauge Single gauge
L78S05C L78S05CV-DG L78S05CV 5 V
L78S75C L78S75CV-DG L78S75CV 7.5 V
L78S09C L78S09CV-DG L78S09CV 9 V
L78S10C L78S10CV-DG L78S10CV 10 V
L78S12C L78S12CV-DG L78S12CV 12 V
L78S15C L78S15CV-DG L78S15CV 15 V
L78S18C L78S18CV 18 V
L78S24C L78S24CV 24 V
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Contents L78S
2/35 DocID2148 Rev 8
Contents
1 Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2 Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4 Test circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6 Typical performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
7 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
8 Packaging mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
9 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
DocID2148 Rev 8 3/35
L78S List of tables
35
List of tables
Table 1. Device summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Table 2. Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Table 3. Thermal data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Table 4. Electrical characteristics of L78S05C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Table 5. Electrical characteristics of L78S75C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Table 6. Electrical characteristics of L78S09C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Table 7. Electrical characteristics of L78S10C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Table 8. Electrical characteristics of L78S12C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Table 9. Electrical characteristics of L78S15C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Table 10. Electrical characteristics of L78S18C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Table 11. Electrical characteristics of L78S24C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Table 12. TO-220 (dual gauge) mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Table 13. TO-220 SG (single gauge) mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Table 14. Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
List of figures L78S
4/35 DocID2148 Rev 8
List of figures
Figure 1. Block diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Figure 2. Pin connections (top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Figure 3. Schematic diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Figure 4. Application circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Figure 5. DC parameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Figure 6. Load regulation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Figure 7. Ripple rejection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Figure 8. Dropout voltage vs. junction temperature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Figure 9. Peak output current vs. input/output differential voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Figure 10. Output impedance vs. frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Figure 11. Output voltage vs. junction temperature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Figure 12. Supply voltage rejection vs. frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Figure 13. Quiescent current vs. junction temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Figure 14. Load transient response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Figure 15. Line transient response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Figure 16. Quiescent current vs. input voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Figure 17. Fixed output regulator. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Figure 18. Constant current regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Figure 19. Circuit for increasing output voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Figure 20. Adjustable output regulator (7 to 30 V). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Figure 21. 0.5 to 10 V regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Figure 22. High current voltage regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Figure 23. High output current with short circuit protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Figure 24. Tracking voltage regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Figure 25. Positive and negative regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Figure 26. Negative output voltage circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Figure 27. Switching regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Figure 28. High input voltage circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Figure 29. High input voltage circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Figure 30. High output voltage regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Figure 31. High input and output voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Figure 32. Reducing power dissipation with dropping resistor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Figure 33. Remote shutdown. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Figure 34. Power AM modulator (unity voltage gain, I
O
£ 1 A) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Figure 35. Adjustable output voltage with temperature compensation . . . . . . . . . . . . . . . . . . . . . . . . 26
Figure 36. Light controllers (V
Omin
= V
XX
+ V
BE
). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Figure 37. Protection against input short-circuit with high capacitance loads . . . . . . . . . . . . . . . . . . . 27
Figure 38. TO-220 (dual gauge) drawing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Figure 39. TO-220 SG (single gauge) drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Figure 40. Tube for TO-220 (dual gauge) (mm.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Figure 41. Tube for TO-220 (single gauge) (mm.). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
DocID2148 Rev 8 5/35
L78S Diagram
35
1 Diagram
Figure 1. Block diagram
Pin configuration L78S
6/35 DocID2148 Rev 8
2 Pin configuration
Figure 2. Pin connections (top view)
72
*5281'*5281'
Figure 3. Schematic diag ram
DocID2148 Rev 8 7/35
L78S Maximum ratings
35
3 Maximum ratings
Note: Absolute maximum ratings are those values beyond which damage to the device may occur.
Functional operation under these condition is not implied.
Table 2. Absolute maximum ratings
Symbol Parameter Value Unit
V
I
DC input voltage for V
O
= 5 to 18V 35 V
for V
O
= 24V 40
I
O
Output current Internally limited
P
D
Power dissipation Internally limited
T
STG
Storage temperature range -65 to 150 °C
T
OP
Operating junction temperature range 0 to 150 °C
Table 3. Thermal data
Symbol Parameter TO-220 Unit
R
thJC
Thermal resistance junction-case 5 °C/W
R
thJA
Thermal resistance junction-ambient 50 °C/W
Figure 4. Application circuits
4
Test circuits L78S
8/35 DocID2148 Rev 8
4 Test circuits
Figure 5. DC parameter
4
Figure 6. Load regulation
4
Figure 7. Ripple rejection
4
DocID2148 Rev 8 9/35
L78S Electri cal ch ara ct er istics
35
5 Electrical characteristics
Refer to the test circuits, T
J
= 25 °C, V
I
= 10 V, I
O
= 500 mA, unless othe rwi s e specif ied .
Table 4. Electrical characteristics of L78S05C
Symbol Parameter Test condi tions Min. Typ. Max. Unit
V
O
Output voltage 4.8 5 5.2 V
V
O
Output voltage I
O
= 1 A, V
I
= 7 V 4.75 5 5.25 V
ΔV
O
Line regulation V
I
= 7 to 25 V 100 mV
V
I
= 8 to 25 V 50
ΔV
O
Load regulation I
O
= 20 mA to 1.5 A 100 mV
I
O
= 2 A 80
I
Q
Quiescent current 8 mA
ΔI
Q
Quiescent current change I
O
= 20 mA to 1 A 0.5 mA
V
I
= 7 to 25 V, I
O
= 20 mA 1.3
ΔV
O
/ΔT Output voltage drift I
O
= 5 mA, T
J
= 0 °C to 70 °C -1.1 mV/°C
eN Output noise voltage B = 10 Hz to 100 kHz 40 µV
SVR Supply voltage rejection f = 120 Hz 54
(1)
dB
V
I
Operating input voltage I
O
≤
1 A 8 V
R
O
Output resistance f = 1 kHz 17 mΩ
I
sc
Short circuit current V
I
= 27 V 500 mA
I
scp
Short circuit peak current 3 A
1. Guaranteed by design.
Ele ctrical characteristics L78S
10/35 DocID2148 Rev 8
Refer to the test circuits, T
J
= 25 °C, V
I
= 12.5 V, I
O
= 500 mA, unless otherwise specified.
Table 5. Electrical characteristics of L78S75C
Symbol Parameter Test condi tions Min. Typ. Max. Unit
V
O
Output voltage 7.15 7.5 7.9 V
V
O
Output voltage I
O
= 1 A, V
I
= 9.5 V 7.1 7.5 7.95 V
ΔV
O
Line regulation V
I
= 9.5 to 25 V 120 mV
V
I
= 10.5 to 20 V 60
ΔV
O
Load regulation I
O
= 20 mA to 1.5 A 140 mV
I
O
= 2 A 100
I
Q
Quiescent current 8 mA
ΔI
Q
Quiescent current change I
O
= 20 mA to 1 A 0.5 mA
V
I
= 9.5 to 25 V, I
O
= 20 mA 1.3
ΔV
O
/ΔT Output voltage drift I
O
= 5 mA, T
J
= 0 °C to 70 °C -0.8 mV/°C
eN Output noise voltage B = 10 Hz to 100 kHz 52 µV
SVR Supply voltage rejection f = 120 Hz 48
(1)
dB
V
I
Operating input voltage I
O
≤
1 A 10.5 V
R
O
Output resistance f = 1 kHz 16 mΩ
I
sc
Short circuit current V
I
= 27 V 500 mA
I
scp
Short circuit peak current 3 A
1. Guaranteed by design.
DocID2148 Rev 8 11/35
L78S Electri cal ch ara ct er istics
35
Refer to the test circuits, T
J
= 25 °C, V
I
= 14 V, I
O
= 500 mA, unless othe rwi s e specif ied .
Table 6. Electrical characteristics of L78S09C
Symbol Parameter Test condi tions Min. Typ. Max. Unit
V
O
Output voltage 8.65 9 9.35 V
V
O
Output voltage I
O
= 1 A, V
I
= 11 V 8.6 9 9.4 V
ΔV
O
Line regulation V
I
= 11 to 25 V 130 mV
V
I
= 11 to 20 V 65
ΔV
O
Load regulation I
O
= 20 mA to 1.5 A 170 mV
I
O
= 2 A 100
I
Q
Quiescent current 8 mA
ΔI
Q
Quiescent current change I
O
= 20 mA to 1 A 0.5 mA
V
I
= 11 to 25 V, I
O
= 20 mA 1.3
ΔV
O
/ΔT Output voltage drift I
O
= 5 mA, T
J
= 0 °C to 70 °C -1 mV/°C
eN Output noise voltage B = 10 Hz to 100 kHz 60 µV
SVR Supply voltage rejection f = 120 Hz 47
(1)
dB
V
I
Operating input voltage I
O
≤
1 A 12 V
R
O
Output resistance f = 1 kHz 17 mΩ
I
sc
Short circuit current V
I
= 27 V 500 mA
I
scp
Short circuit peak current 3 A
1. Guaranteed by design.
Ele ctrical characteristics L78S
12/35 DocID2148 Rev 8
Refer to the test circuits, T
J
= 25 °C, V
I
= 15 V, I
O
= 500 mA, unless othe rwi s e specif ied .
Table 7. Electrical characteristics of L78S10C
Symbol Parameter Test condi tions Min. Typ. Max. Unit
V
O
Output voltage 9.5 10 10.5 V
V
O
Output voltage I
O
= 1 A, V
I
= 12.5 V 9.4 10 10.6 V
ΔV
O
Line regulation V
I
= 12.5 to 30 V 200 mV
V
I
= 14 to 22 V 100
ΔV
O
Load regulation I
O
= 20 mA to 1.5 A 240 mV
I
O
= 2 A 150
I
Q
Quiescent current 8 mA
ΔI
Q
Quiescent current change I
O
= 20 mA to 1 A 0.5 mA
V
I
= 12.5 to 30 V, I
O
= 20 mA 1
ΔV
O
/ΔT Output voltage drift I
O
= 5 mA, T
J
= 0 °C to 70 °C -1 mV/°C
eN Output noise voltage B = 10 Hz to 100 kHz 65 µV
SVR Supply voltage rejection f = 120 Hz 47
(1)
dB
V
I
Operating input voltage I
O
≤
1 A 13 V
R
O
Output resistance f = 1 kHz 17 mΩ
I
sc
Short circuit current V
I
= 27 V 500 mA
I
scp
Short circuit peak current 3 A
1. Guaranteed by design.
DocID2148 Rev 8 13/35
L78S Electri cal ch ara ct er istics
35
Refer to the test circuits, T
J
= 25 °C, V
I
= 19 V, I
O
= 500 mA, unless othe rwi s e specif ied .
Table 8. Electrical characteristics of L78S12C
Symbol Parameter Test condi tions Min. Typ. Max. Unit
V
O
Output voltage 11.5 12 12.5 V
V
O
Output voltage I
O
= 1 A, V
I
= 14.5 V 11.4 12 12.6 V
ΔV
O
Line regulation V
I
= 14.5 to 30 V 240 mV
V
I
= 16 to 22 V 120
ΔV
O
Load regulation I
O
= 20 mA to 1.5 A 240 mV
I
O
= 2 A 150
I
Q
Quiescent current 8 mA
ΔI
Q
Quiescent current change I
O
= 20 mA to 1 A 0.5 mA
V
I
= 14.5 to 30 V, I
O
= 20 mA 1
ΔV
O
/ΔT Output voltage drift I
O
= 5 mA, T
J
= 0 °C to 70 °C -1 mV/°C
eN Output noise voltage B =10 Hz to 100 kHz 75 µV
SVR Supply voltage rejection f = 120 Hz 47
(1)
dB
V
I
Operating input voltage I
O
≤
1 A 15 V
R
O
Output resistance f = 1 kHz 18 mΩ
I
sc
Short circuit current V
I
= 27 V 500 mA
I
scp
Short circuit peak current 3 A
1. Guaranteed by design.
Ele ctrical characteristics L78S
14/35 DocID2148 Rev 8
Refer to the test circuits, T
J
= 25 °C, V
I
= 23 V, I
O
= 500 mA, unless othe rwi s e specif ied .
Table 9. Electrical characteristics of L78S15C
Symbol Parameter Test condi tions Min. Typ. Max. Unit
V
O
Output voltage 14.4 15 15.6 V
V
O
Output voltage I
O
= 1 A, V
I
= 17.5 V 14.25 15 15.75 V
ΔV
O
Line regulation V
I
= 17.5 to 30 V 300 mV
V
I
= 20 to 26 V 150
ΔV
O
Load regulation I
O
= 20 mA to 1.5 A 300 mV
I
O
= 2 A 150
I
Q
Quiescent current 8 mA
ΔI
Q
Quiescent current change I
O
= 20 mA to 1 A 0.5 mA
V
I
= 17.5 to 30 V, I
O
= 20 mA 1
ΔV
O
/ΔT Output voltage drift I
O
= 5 mA, T
J
= 0 °C to 70 °C -1 mV/°C
eN Output noise voltage B =10 Hz to 100 kHz 90 µV
SVR Supply voltage rejection f = 120 Hz 46
(1)
dB
V
I
Operating input voltage I
O
≤
1 A 18 V
R
O
Output resistance f = 1 kHz 19 mΩ
I
sc
Short circuit current V
I
= 27 V 500 mA
I
scp
Short circuit peak current 3 A
1. Guaranteed by design.
DocID2148 Rev 8 15/35
L78S Electri cal ch ara ct er istics
35
Refer to the test circuits, T
J
= 25 °C, V
I
= 26 V, I
O
= 500 mA, unless othe rwi s e specif ied .
Table 10. Electrical characteristics of L78S18C
Symbol Parameter Test condi tions Min. Typ. Max. Unit
V
O
Output voltage 17.1 18 18.9 V
V
O
Output voltage I
O
= 1 A, V
I
= 20.5 V 17 18 19 V
ΔV
O
Line regulation V
I
= 20.5 to 30 V 360 mV
V
I
= 22 to 28 V 180
ΔV
O
Load regulation I
O
= 20 mA to 1.5 A 360 mV
I
O
= 2 A 200
I
Q
Quiescent current 8 mA
ΔI
Q
Quiescent current change I
O
= 20 mA to 1 A 0.5 mA
V
I
= 20.5 to 30 V, I
O
= 20 mA 1
ΔV
O
/ΔT Output voltage drift I
O
= 5 mA, T
J
= 0 °C to 70 °C -1 mV/°C
eN Output noise voltage B =10 Hz to 100 kHz 110 µV
SVR Supply voltage rejection f = 120 Hz 43
(1)
dB
V
I
Operating input voltage I
O
≤
1 A 21 V
R
O
Output resistance f = 1 kHz 22 mΩ
I
sc
Short circuit current V
I
= 27 V 500 mA
I
scp
Short circuit peak current 3 A
1. Guaranteed by design.
Ele ctrical characteristics L78S
16/35 DocID2148 Rev 8
Refer to the test circuits, T
J
= 25 °C, V
I
= 33 V, I
O
= 500 mA, unless othe rwi s e specif ied .
Table 11. Electrical characteristics of L78S24C
Symbol Parameter Test condi tions Min. Typ. Max. Unit
V
O
Output voltage 23 24 25 V
V
O
Output voltage I
O
= 1 A, V
I
= 27 V 22.82425.2 V
ΔV
O
Line regulation V
I
= 27 to 38 V 480 mV
V
I
= 30 to 36 V 240
ΔV
O
Load regulation I
O
= 20 mA to 1.5 A 480 mV
I
O
= 2 A 300
I
Q
Quiescent current 8 mA
ΔI
Q
Quiescent current change I
O
= 20 mA to 1 A 0.5 mA
V
I
= 27 to 38 V, I
O
= 20 mA 1
ΔV
O
/ΔT Output voltage drift I
O
= 5 mA, T
J
= 0 °C to 70 °C -1.5 mV/°C
eN Output noise voltage B = 10 Hz to 100 kHz 170 µV
SVR Supply voltage rejection f = 120 Hz 42
(1)
dB
V
I
Operating input voltage I
O
≤
1 A 27 V
R
O
Output resistance f = 1 kHz 28 mΩ
I
sc
Short circuit current V
I
= 27 V 500 mA
I
scp
Short circuit peak current 3 A
1. Guaranteed by design.
DocID2148 Rev 8 17/35
L78S Typical performanc e
35
6 Typical performance
Figure 8. Dropout voltage vs. junction
temperature Figure 9. Peak output current vs. input/output
differential voltage
Figure 10. Output impedance vs. frequency Figure 11. Output voltage vs. junction
temperature
Typical performa nce L78S
18/35 DocID2148 Rev 8
Figure 12. Supply voltage rejection vs.
frequency Figure 13. Quiescent current vs. junction
temperature
Figure 14. Load transient response Figure 15. Line transient response
Figure 16. Quiescent current vs. input voltage
DocID2148 Rev 8 19/35
L78S Typical performanc e
35
1. Although no output capacitor is need for stability, it does improve transient response.
2. Required if regulator is located an appreciable distance from power supply filter.
Figure 17. Fixed output regulator
Figure 18. Constant current regulator
,
2
9
;;;;
5
,
G
4
Figure 19. Circuit for increasing output voltage
,5 ,G
92 9;;;;555,G5
Ż
4
Typical performa nce L78S
20/35 DocID2148 Rev 8
Figure 20. Adjustable output regulator (7 to 30 V)
Figure 21. 0.5 to 10 V regulator
V
O
=V
XX
R
4
/R
1
DocID2148 Rev 8 21/35
L78S Typical performanc e
35
Figure 22. High current voltage regulator
5
,2 ,5(*4,5(*B
9
BBBB
%(4
B
9%(4
5 BBBBBBBBBBBBBB
,5(4,4E4
4
Figure 23. High output current with short circuit protection
56&6& 9%(%(44,6&6&
4
Typical performa nce L78S
22/35 DocID2148 Rev 8
Figure 24. Tracking voltage regulator
4
Figure 25. Positive and negative regulator
DocID2148 Rev 8 23/35
L78S Typical performanc e
35
Figure 26. Negative output voltage circuit
Figure 27. Switching regulator
Figure 28. High input voltage circuit
9,1 9,99=9%(%(
4
Typical performa nce L78S
24/35 DocID2148 Rev 8
Figure 29. High input voltage circuit
4
Figure 30. High output v oltage regulator
4
Figure 31. High input and output v oltage
92 9;;;;9=
4
DocID2148 Rev 8 25/35
L78S Typical performanc e
35
Figure 32. Reducing power dissipation with dropping resistor
9999 9
5 BB,PL,PL
BBBBB
QQ
BBBBBBB
;;;;
BBBBB
'52
BBBBBBB
3PD[PD[
BBBBBB
,2PD[[,GPD[PD[
4
Figure 33. Remote shutdown
4
Typical performa nce L78S
26/35 DocID2148 Rev 8
Note: The circuit performs well up to 100 kHz.
Note: Q
2
is connected as a diode in order to compensate the variation of the Q
1
V
BE
with the
temperature. C allows a slow rise time of the V
O
.
Figure 34. Power AM modulator (unity voltage gain, I
O
≤
1 A)
4
Figure 35. Adjustable output voltage with temperature compensation
92 9;;559%(
4
DocID2148 Rev 8 27/35
L78S Typical performanc e
35
1. Application with high capacitance loads and an output voltage greater than 6 volts need an external diode
(see Figure 30 on page 24) to protect the device against input short circuit. In this case the input voltage
falls rapidly while the output voltage decrease slowly. The capacitance discharges by means of the Base-
Emitter junction of the series pass transistor in the regulator. If the energy is sufficiently high, the transistor
may be destroyed. The external diode by-passes the current from the IC to ground.
Figure 36. Light controllers (V
Omin
= V
XX
+ V
BE
)
92ULVHVZKHQWKHOLJKWJRHVXS
92IDOOVZKHQW KHO LJK W JRHVXS
Figure 37. Protection against input short-cir cuit with high capacitance loads
4
Package mechanical data L78S
28/35 DocID2148 Rev 8
7 Package mechanical data
In order to meet environmental requirements, ST offers these devices in different grades of
ECOPACK
®
packages, depending on their level of environmental compliance. ECOPACK
®
specifications, grade definitions and product status are available at: www.st.com.
ECOPACK
®
is an ST trademark.
DocID2148 Rev 8 29/35
L78S Package mechanical data
35
Figure 38. TO-220 (dual gauge) drawing
BW\SH$B5HYB7
Package mechanical data L78S
30/35 DocID2148 Rev 8
Table 12. TO-220 (dual gauge) mechanical data
Dim. mm
Min. Typ. Max.
A4.40 4.60
b0.61 0.88
b1 1.14 1.70
c0.48 0.70
D 15.25 15.75
D1 1.27
E 10 10.40
e2.40 2.70
e1 4.95 5.15
F1.23 1.32
H1 6.20 6.60
J1 2.40 2.72
L13 14
L1 3.50 3.93
L20 16.40
L30 28.90
∅
P3.75 3.85
Q2.65 2.95
DocID2148 Rev 8 31/35
L78S Package mechanical data
35
Figure 39. TO-220 SG (single gauge) drawing
BUHY'
Package mechanical data L78S
32/35 DocID2148 Rev 8
Table 13. TO-220 SG (single gauge) mechanical data
Dim. mm
Min. Typ. Max.
A 4.40 4.60
b 0.61 0.88
b1 1.14 1.70
c 0.48 0.70
D 15.25 15.75
E 10 10.40
e 2.40 2.70
e1 4.95 5.15
F 0.51 0.60
H1 6.20 6.60
J1 2.40 2.72
L13 14
L1 3.50 3.93
L20 16.40
L30 28.90
∅
P 3.75 3.85
Q 2.65 2.95
DocID2148 Rev 8 33/35
L78S Packaging mechanical data
35
8 Packaging mechanical data
Figure 40. Tube for TO-220 (dual gauge) (mm.)
Figure 41. Tube for TO-220 (single gauge) (mm.)
Revision history L78S
34/35 DocID2148 Rev 8
9 Revision history
Table 14. Document revision history
Date Revision Changes
07-Sep-2006 2 Order codes updated.
20-Mar-2008 3 Added: Tabl e 1 on page 1.
22-Mar-2010 4 Added: Table 20 on pag e 32, Figure 38 on page 33, Figure 39 on page 34,
Figure 40 and Figure 41 on page 33.
08-Feb-2012 5 Added: order codes L78S05CV-DG, L78S12CV-DG and L78S15CV-DG
Table 13 on page 35.
09-Mar-2012 6 Added: order codes L78S09CV-DG Table 13 on page 35.
15-May-2012 7 Added: order codes L78S75CV-DG and L78S10CV-DG Table 13 on page 35.
10-Mar-2014 8
Part numbers L78Sxx and L78SxxC changed to L78S.
Modified the title, the features and the description in cover page.
Removed TO-3 package.
Updated Table 1: Device summary , Section 2: Pin configuration, Section 3:
Maximum ratings, Section 4: Test circuit s, Section 5: Electrical
characteristics,Section 6: Typical performance, Se ction 7: Package
mechanical data, Section 9: Order codes.
Added Section 8: Packaging mechanical data.
Minor text changes.
DocID2148 Rev 8 35/35
L78S
35
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