Datasheet

LM117 LM317A LM317 3-Terminal Adjustable Regulator

May 1996

LM117 LM317A LM317 3-Terminal Adjustable Regulator
General Description
The LM117 series of adjustable 3-terminal positive voltage regulators is capable of supplying in excess of 1 5A over a 1 2V to 37V output range They are exceptionally easy to use and require only two external resistors to set the output voltage Further bothline and load regulation are better than 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 only in IC’s Included on the chip are current limit thermal overload protection and safe area protection All overloadprotection circuitry remains fully functional even if the adjustment terminal is disconnected Normally no capacitors are needed unless the device is situated 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 ratioswhich are difficult to achieve with standard 3-terminal regulators Besides replacing fixed regulators the LM117 is useful in a wide variety of other applications Since the regulator is ‘‘floating’’ and sees only the input-to-output differential voltage supplies of several hundred volts can be regulated as long as the maximum input to output differential is not exceeded i e avoid short-circuitingthe output Also it makes an especially simple adjustable switching regulator a programmable output regulator 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 clamping the adjustment terminal to ground which programs the output to 1 2V where most loads draw littlecurrent For applications requiring greater output current see LM150 series (3A) and LM138 series (5A) data sheets For the negative complement see LM137 series data sheet LM117 Series Packages and Power Capability Part Number Suffix K H T E S Package TO-3 TO-39 TO-220 LCC TO-263 Rated Power Dissipation 20W 2W 20W 2W 4W Design Load Current 1 5A 0 5A 1 5A 0 5A 1 5A

Features
Y Y

Y

Y Y Y Y Y YGuaranteed 1% output voltage tolerance (LM317A) Guaranteed max 0 01% V line regulation (LM317A) Guaranteed max 0 3% load regulation (LM117) Guaranteed 1 5A output current Adjustable output down to 1 2V Current limit constant with temperature P a Product Enhancement tested 80 dB ripple rejection Output is short-circuit protected

Typical Applications
1 2V–25V Adjustable Regulator DigitallySelected Outputs

TL H 9063 – 1

Full output current not available at high input-output voltages Needed if device is more than 6 inches from filter capacitors Optional improves transient response Output capacitors in the range of 1 mF to 1000 mF of aluminum or tantalum electrolytic are commonly used to provide improved output impedance and rejection of transients VOUT e 1 25V

1

a

R2 R1J

TL H 9063 – 2

a IADJ(R2)

Sets maximum VOUT

C1996 National Semiconductor Corporation

TL H 9063

RRD-B30M56 Printed in U S A

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www national com

Absolute Maximum Ratings (Note 1)
If Military Aerospace specified devices are required please contact the National Semiconductor Sales Office Distributors for availability and specifications (Note 2) Power DissipationInternally Limited a 40V b 0 3V Input-Output Voltage Differential
b 65 C to a 150 C Storage Temperature Lead Temperature Metal Package (Soldering 10 seconds) 300 C Plastic Package (Soldering 4 seconds) 260 C ESD Tolerance (Note 5) 3 kV

Operating Temperature Range
LM117 LM317A LM317
b 55 C s TJ s a 150 C b 40 C s TJ s a 125 C 0 C s TJ s a 125 C

Preconditioning
Thermal Limit Burn-In All...