2• Specified 1% Output Voltage Tolerance
• Specified Max. 0.01%/ V Line Regulation
• Specified Max. 0.3% Load Regulation (LM117)
• Specified 1.5A Output Current
• Adjustable Output Downto 1.2V
• Current Limit Constant With Temperature
Product Enhancement Tested
• 80 dB Ripple Rejection
• Outputis Short-Circuit Protected
The LM117 series of adjustable 3-terminal positive
voltage regulatorsis capable ofsupplyingin excess
of1.5A over a 1.2V to 37V outputrange. They are
exceptionally easy to use and require only two
externalresistorsto setthe output voltage. Further.
bothline andloadregulation are betterthan standard
fixed regulators. Also, the LM117 is packaged in
standard transistor packages which are easily
mounted and handled.
In addition to higher performance than fixed
regulators, the LM117 series offers full overload
protection available onlyinIC's. Included onthe chip
are currentlimit, thermaloverload protection and safe
area protection. All overload protection circuitry
remains fully functional even if the adjustment
Normally, no capacitors are needed unlessthe device
is situated more than 6inches from theinputfilter
capacitorsin which case aninputbypassis needed.
An optionaloutputcapacitorcan be addedtoimprove
transientresponse. The adjustmentterminalcan be
bypassedto achieve very high ripple rejection ratios
which are difficultto achieve with standard 3-terminal
Besides replacing fixed regulators, the LM117 is
usefulin a wide variety of other applications. Since
the regulatoris'floating and sees onlytheinput-to-
output differential voltage, supplies of several
hundred volts can be regulated as long as the
maximum inputto outputdifferentialis notexceeded.
i.e., avoid short-circuitingthe output.
Also, it makes an especially simple adjustable
switchingregulator, a programmable outputregulator.
or by connecting a fixed resistor between the
adjustment pin and output, the LM117 can be used
as a precision current regulator. Supplies with
electronic shutdown can be achieved by clampingthe
adjustmentterminalto ground which programs the
outputto1.2V where mostloads drawlittle current.
Forapplicationsrequiring greateroutputcurrent, see
LM150 series (3A) and LM138 series (5A) data
sheets. Forthe negative complement, see LM137
series data sheet.