LM317, NCV317
1.5 A Adjustable Output,
Positive Voltage Regulator
The LM317 is an adjustable 3−terminal positive voltage regulator
capable of supplying in excess of 1.5 A over an output voltage range of
1.2 V to 37 V. This voltage regulator is exceptionally easy to use and
requires only two external resistors to set the output voltage. Further, it
employs internal current limiting, thermal shutdown and safe area
compensation, making it essentially blow−out proof.
The LM317 serves a wide variety of applications including local, on
card regulation. This device can also be used to make a programmable
output regulator, or by connecting a fixed resistor between the
adjustment and output, the LM317 can be used as a precision current
regulator.
Features
http://onsemi.com
1
2
3
D
2
PAK−3
D2T SUFFIX
CASE 936
•
•
•
•
•
•
•
Output Current in Excess of 1.5 A
Output Adjustable between 1.2 V and 37 V
Internal Thermal Overload Protection
Internal Short Circuit Current Limiting Constant with Temperature
Output Transistor Safe−Area Compensation
Floating Operation for High Voltage Applications
Available in Surface Mount D
2
PAK−3, and Standard 3−Lead
Transistor Package
•
Eliminates Stocking many Fixed Voltages
•
Pb−Free Packages are Available
V
in
Heatsink surface (shown as terminal 4 in
case outline drawing) is connected to Pin 2.
TO−220
T SUFFIX
CASE 221A
1
2
3
Pin 1. Adjust
2. V
out
3. V
in
Heatsink surface connected to Pin 2.
LM317
V
out
R
1
240
Adjust
+ C **
O
1.0
mF
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 10 of this data sheet.
I
Adj
C
in
*
0.1
mF
R
2
DEVICE MARKING INFORMATION
See general marking information in the device marking
section on page 10 of this data sheet.
**
C
in
is required if regulator is located an appreciable distance from power supply filter.
** C
O
is not needed for stability, however, it does improve transient response.
R
V out
+
1.25 V 1
)
2
R1
)
I
R
Adj 2
Since I
Adj
is controlled to less than 100
mA,
the error associated with this term is
negligible in most applications.
Figure 1. Standard Application
©
Semiconductor Components Industries, LLC, 2005
1
August, 2005 − Rev. 8
Publication Order Number:
LM317/D