LM317L

Manufacturer Part NumberLM317L
ManufacturerNational Semiconductor
LM317L datasheet
 
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LM317L
3-Terminal Adjustable Regulator
General Description
The LM317L is an adjustable 3-terminal positive voltage
regulator capable of supplying 100mA over a 1.2V to 37V
output range. It is exceptionally easy to use and requires
only two external resistors to set the output voltage. Further,
both line and load regulation are better than standard fixed
regulators. Also, the LM317L is available packaged in a stan-
dard TO-92 transistor package which is easy to use.
In addition to higher performance than fixed regulators, the
LM317L offers full overload protection. Included on the chip
are current limit, thermal overload protection and safe area
protection. All overload protection circuitry remains fully func-
tional even if the adjustment terminal is disconnected.
Normally, no capacitors are needed unless the device is situ-
ated more than 6 inches from the input filter capacitors in
which case an input bypass is needed. An optional output
capacitor can be added to improve transient response. The
adjustment terminal can be bypassed to achieve very high
ripple rejection ratios which are difficult to achieve with stan-
dard 3-terminal regulators.
Besides replacing fixed regulators, the LM317L is useful in a
wide variety of other applications. Since the regulator is
“floating” and sees only the input-to-output differential volt-
age, supplies of several hundred volts can be regulated as
long as the maximum input-to-output differential is not ex-
ceeded.
Connection Diagrams
TO-92 Plastic package
© 2000 National Semiconductor Corporation
Also, it makes an especially simple adjustable switching
regulator, a programmable output regulator, or by connecting
a fixed resistor between the adjustment and output, the
LM317L can be used as a precision current regulator. Sup-
plies with electronic shutdown can be achieved by clamping
the adjustment terminal to ground which programs the out-
put to 1.2V where most loads draw little current.
The LM317L is available in a standard TO-92 transistor
package, the SO-8 package, and 6-Bump micro SMD pack-
age. The LM317L is rated for operation over a −25˚C to
125˚C range.
Features
n Adjustable output down to 1.2V
n Guaranteed 100 mA output current
n Line regulation typically 0.01%V
n Load regulation typically 0.1%
n Current limit constant with temperature
n Eliminates the need to stock many voltages
n Standard 3-lead transistor package
n 80 dB ripple rejection
n Available in TO-92, SO-8, or 6-Bump micro SMD
package
n Output is short circuit protected
n See AN-1112 for micro SMD considerations
DS009064-4
DS009064
March 2000
8-Pin SOIC
DS009064-5
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