LM317 Datasheet, PDF (1/6 Pages) ON Semiconductor – 1.5 A Adjustable Output, Positive Voltage Regulator

LM317
New Product
Vishay
formerly General Semiconductor
3-Terminal Adjustable Output Positive Voltage Regulators
Pin Arrangement
TO-220
(LM317CT)
3
2
1
TO-263
(LM317CM)
3
2
1
1. Adjust
2. Vout
3. Vin
Heatsink is connected to pin 2
Vin
Cin
0.1µF
Standard Application
LM317
R1
IADJ Adjust ^240Ω
R2
Vout
Co
1µF
Notes:
Cin is required if regulator is located an appreciable distance from power
supply filter.
Co is not needed for stability, however, it does improve transient response.
Vout = 1.25V (1 + R2/ R1) + IAdj R2
Since IAdj is controlled to less than 100µA, the error associated with this
term is negligible in most applications
Input
Functional Block Diagram
3
Description
The LM317 is an adjustable 3-terminal positive voltage
regulator capable of supplying in excess of 1.5A over an
output voltage range of 1.2V to 37V. 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 compen-
sation, making it essentially blow-out proof.
Features
• Output current in excess of 1.5 ampere
• Output adjustable between 1.2V and 37V
• Internal thermal overload protection
• Internal short-circuit current limiting
constant with temperature
• Output transistor safe-area compensation
• Floating operation for high voltage applications
• Eliminates stocking many fixed voltages
Mechanical Data
Case: TO-220 and TO-263 packages
Weight: approx. 1.35g
Case outlines are on the back page.
+
--
Voltage
Reference
Vadj
1
Protection
Circuitry
Rlimit
2
Output
Maximum Ratings Ratings at 25°C ambient temperature unless otherwise specified.
Parameter
Symbol
Input-Output Voltage Differential
Junction-to-Case Thermal Resistance
TO-220
TO-263
Vi-Vo
RθJC
Power Dissipation, 25°C Case Temperature
PD
Operating Junction Temperature Range
TJ
Storage Junction Temperature Range
Tstg
Document Number 74809
30-Oct-02
Value
40
3.0
3.0
15
0 to +125
–65 to +150
Unit
Vdc
°C
W
°C
°C
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