Lm78Sxx

L78Sxx
L78SxxC
2 A positive voltage regulators
Features
■

Output current to 2 A

■

Output voltages of 5; 7.5; 9; 10; 12; 15; 18; 24 V

■

Thermal overload protection

■

Short circuit protection

■

Output transition SOA protection

Description

TO-220

TO-3

The L78Sxx series of three-terminal positive
regulators is available in TO-220 and TO-3
packages and withseveral fixed output voltages,
making it useful in a wide range of applications.
These regulators can provide local on-card
regulation, eliminating the distribution problems
associated with single point regulation. Each type
employs internal current limiting, thermal shutdown and safe area protection, making it
essentially indestructible. If adequate heat sinking
is provided, they candeliver 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.

Table 1.

Device summary
Part numbers
L78S05

L78S09

L78S12

L78S18

L78S05C

L78S09C

L78S12C

L78S18C

L78S75

L78S10

L78S15

L78S24

L78S75C

L78S10C

L78S15C

L78S24CMarch 2008

Rev 3

1/31
www.st.com

31

Contents

L78Sxx - L78SxxC

Contents
1

Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2

Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3

Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 5

4

Test circuits

5

Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

6

Typical performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

7

Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

8

Ordercodes

9

Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

2/31

............................................... 6

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

L78Sxx - L78SxxC

1

Diagram

Figure 1.

Diagram

Block diagram

3/31

Pin configuration

L78Sxx -L78SxxC

2

Pin configuration

Figure 2.

Pin connections (top view)

TO-220

Figure 3.

4/31

Schematic diagram

TO-3

L78Sxx - L78SxxC

Maximum ratings

3

Maximum ratings

Table 2.

Absolute maximum ratings

Symbol

Parameter

Value
for VO= 5 to 18V

35

for VO= 24V

Unit

40

VI

DC input voltage

IO

Output current

Internally limitedPD

Power dissipation

Internally limited

TSTG

Storage temperature range

TOP

V

-65 to 150

Operating junction temperature range

for L78Sxx

°C

-55 to 150
°C

for L78SxxC

0 to 150

Note:

Absolute maximum ratings are those values beyond which damage to the device may occur.
Functional operation under these condition is not implied.

Table 3.

Thermal dataSymbol

Parameter

TO-220

TO-3

Unit

RthJC

Thermal resistance junction-case

5

4

°C/W

RthJA

Thermal resistance junction-ambient

50

35

°C/W

Figure 4.

Application circuits

5/31

Test circuits

4

Test circuits

Figure 5.

DC parameter

Figure 6.

Load regulation

Figure 7.

Ripple rejection

6/31

L78Sxx - L78SxxC

L78Sxx -L78SxxC

Electrical characteristics

5

Electrical characteristics

Table 4.

Electrical characteristics of L78S05 (refer to the test circuits, TJ = 25 °C, VI = 10 V,
IO = 500 mA, unless otherwise specified)

Symbol

Parameter

VO

Output voltage

ΔVO

Line regulation

ΔVO

Load regulation

IQ
ΔIQ
ΔVO/ΔT

IO = 1A, VI = 7V

Min.

Typ.

Max.

Unit

4.8...