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1/14 3-terminal adjust a ble regula t o r LM317L / lm317 lf d e s c r i p t i o n the lm 317 is an adjustable 3-terminal positive voltage regulator capable of supply i ng 100m a 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, it em ploy s internal current lim iting, therm a l shutdown and safe area com p ensation, m a king it essentially blow-out proof. also, the lm317 is available packaged in a standard to-92 transistor package which is easy to use. the lm 317 serves a wide variety of applications including local, on card regulation. this device can also be used to m a ke a program m a ble output regulator, or by connecting a fixed resistor between the adjustm ent and output, the lm317 can be used as a precision current regulator. f e a t u r e s p i n c o n n e c t i o n adjustable output down to 1.2v guaranteed 100 m a output current line regulation ty pically 0.01%/v load regulation ty pically 0.1% current lim it constant with tem p erature elim inates the need to stock m a ny voltages 80 db ripple rejection output is short circuit protected tiger electronic co.,ltd
lm317 2/14 schema tic diagram
lm317 3/14 absolute maximum ratings (ta=25 c) characteristic symbol min. max. unit input-output voltage differential vi/ao -0.3 40 v power dissipation p d - internally limited w operating junction temperature range tj -25 125 c lead temperature (soldering, 4 seconds) t l - 250 c storage temperature range tstg -55 150 c electrical characteristics (unless otherwise specified: vi-vo=5.0v; io=40ma; tj=0~125 c; imax=100ma and pmax=625mw ) characteristics test conditions symbol min. typ. max. unit line regulation tj=25 , i l 20ma 3v (v in -v out ) 40v regline - 0.01 0.05 % /v load regulation tj=25 , 5ma i out i max regload - 0.1 0.5 % adjustment pin current - iadj - 50 100 a adjustment pin current change 5ma i l 100ma 3v (v in -v out ) 40v, p 625mw ? iadj - 0.2 6 a reference voltage 3v (v in -v out ) 40v, 5ma i out 100ma, p 625mw vref 1.15 1.25 1.35 v line regulation 3v (v in -v out ) 40v,i 20ma regline - 0.02 0.05 %/v load regulation 5ma i out 100ma regload - 0.3 1.2 % temperature stability t min tj t max ts - 0.65 - % (v i n -v out ) 40v - 3.5 17 minimum load current 3v (v in -v out ) 15v i l min 1.5 6 ma 3v (v in -v out ) 13v 40 200 260 ma current limit (v in -v out ) =40v imax 25 50 70 ma rms noise % of vo tj=25 , 10hz f 10khz n - 0.003 0.008 % v out =10v, f=120hz, c adj =0 65 80 ripple rejection c adj =10 f rr 66 80 db long-term stability tj=125 , 1000hours s - 0.3 1 %
lm317 4/14 applica t ion informa t ion 1. basic circuit operation in operation, the lm 317 develops a nominal 1.25v reference voltage, vref, between the output and adjustm e nt term inal. the reference voltage is im pressed across program resistor r1 and, since the voltage is constant, a constant current i1 then flows through the output set resistor r2, giving an output voltage of v o u t = v r e f ( 1 + r 2 / r 1 ) + i a d j * ( r 2 ) since the 100 a current from the adjustm e nt term inal represents an error term, the lm317 was designed to m i nim i ze iadj and m a ke it very constant with line and load changes. to do this, all quiescent operating current is returned to the output establishing a m i nim u m load current requirem e nt. if there is insufficient load on the output, the output will rise. figure: basic circuit configuration r1 r2 ll v v ad j i v i v ad j 1 re ou in ou 2. load regulation the lm 317 is capable of providing extremely good load regulation, but a few precaut i ons are nee d ed to obt a in m a xi m u m perform ance. for best perf orm a nce, the programm i ng resistor (r1) shoul d be co nne cted as clos e to t h e regula t or as possi ble t o m i ni m i ze line drops which ef fecti v ely appear in series with the reference, t h ere b y degradi n g regulat io n. the gro und end of r2 ca n b e returned ne ar the loa d groun d to p r ovide rem o te groun d se n s ing an d i m prove loa d reg u la tio n reg u lat o r with li ne resistance i n o u t p u t l e a d r1 r2 l m 317l v v ad j v ou t in ou t rs 240 v in w317l w317l 3.external capacitors a 0 . 1 f disc or 1. 0 f tant alum inpu t by pas s capac itor (cin) is re co m m e nded to reduce the sensitivity to input line im pedance. t h e ad j u stm e nt term inal m a y be by passe d to gro u n d to im pro v e ripp le rejecti o n . this ca paci tor (cadj) prevents ri pple from bein g am plified as t h e out pu t v o lta ge is increase d . a 10 f cap acitor sho u l d im prove ripple rejec tion a b o u t 15db a t 12 0hz i n a
lm317 5/14 10v application. althou gh t he lm 317 is stable with no output capacitance, like any feedback circuit , cer tain va lues of e x terna l ca paci ta nce ca n caus e excessive ringing. a n output capac ita nce (co) in t h e form of a 1.0 f tantal um or 25 f alum inu m ele c trolytic capacitor on the output swam ps this effect and insures stability. 4. protection diodes when external capacitors are used with an y ic regulator it is som e tim es necessary to add protection diodes to prevent the capacitors from discharging through low current points into the regulator. most 10 f capacitors have low enough internal series resistance to deliver 20a spikes wh en shorted. although the surge is short, there is enough energy to dam a ge parts of the ic. when an output capacitor is connected to a regulator and the input is shorted, the output capacitor will discharge into the output of the regulator. the discharge current depends on the value of the capacitor, the output voltage of the regulator, and the rate of decrease of vin . in the lm317, this discharge path is through a large junction that is able to sustain a 2a surge with no probl em . this is not true of other ty pes of positive regulators. for output capacitors of 25 f or less, the lm317?s ballast resistors and output structure lim it the peak current to a low enough level so that there is no need to use a protection diode. the by pass capacitor on the adjustm e nt term inal can discharge through a low current junction. discharge occurs when either the input or output is shorted. internal to the lm317 is a 50? resistor which limits the peak discharge current. no protection is needed for output voltages of 25v or less and 10 f capacitance. figure in right shows an lm 317 with protection diodes included for use with outputs greater than 25v and high values of output capacitance. regulator with protection diodes r1 r2 l m 317l v ad j v v ou t in ou t 240 v in d1 i n 4 0 0 d2 in 4 0 0 c1 + c2 10u w317l
lm317 6/14 applica t ion circuit *sets m a xim u m v out d i g i t a l l y s e l e c t e d o u t p u t s h i g h g a i n a m p l i f i e r 12 r1 240 a d j u s t a b l e c u r r e n t l i m i t e r p r e c i s i o n c u r r e n t l i m i t e r slow t u rn-on 15v regulator +sold tantalum im proved ripple rejection *dischar ges c1 if output is shorted to ground a d j u s t a b l e r e g u l a t o r w i t h
lm317 7/14 short circuit current is approximately 600mv/r3, at 25ma output only 3/4v of drop occurs in r3 and r4 high s t ability 10v regulator adjustable regulator with current lim iter 0 v ~ 3 0 v r e g u l a t o r c u r r e n t p o w e r f o l l o w e r adjusting multiple on-card regulators with single control
lm317 8/14 *minim um load current=2m a 100m a current regulator 1.2v~12v regulator with 50m a constant current m i n i m u m p r o g r a m c u r r e n t b a t t e r y c h a r g e r f o r n i c k e l - c a d m i u m b a t t e r i e s * m i n i m u m o u t p u t = 1 . 2 v * s e t s p e a k c u r r e n t , i p e a k = 0 . 6 v / r 1 * * 1000 f is recom m e nded to filter out any input transients 5v logic regulator with electronic shutdown current lim ited 6v char ger
lm317 9/14 short circuit protected 80v supply q 1 , q 2:n s d 134 or sim ila r c1 ,c2 : 1 f , 200v m y la r** *h e a t sink basic high v o ltage regulator
lm317 10/14 q 1 , q 2:n s d 134 or sim ila r c 1 , c 2: 1 f , 200v m y la r** *h e a t sink ** m y la r is a re giste r e d tra d e m a r k of d u pont c o . precision high v o ltage regulator t r acking regulator regulator with t r im m a ble output v o ltage
lm317 11 / 1 4 precision reference with short-circuit proof output a d j u s t a b l e r e g u l a t o r p r o t e c t e d ( b u l l e t p r o o f ) l a m p f l a s h e r l a m p d r i v e r
lm317 12/14 characteristics cur ves
lm317 11 / 1 4 precision reference with short-circuit proof output a d j u s t a b l e r e g u l a t o r p r o t e c t e d ( b u l l e t p r o o f ) l a m p f l a s h e r l a m p d r i v e r
lm317 14/14 outline dra wing t o - 9 2 u n i t : m m sot - 89-3l unit:m m

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