View L431L_915745.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

niko-sem L431L 1 1.24v low-v oltage adjustable precision shunt regulator general description the L431L is a three-terminal adjustable shunt regulator utilizin g an a ccurate 1.24v ban d gap reference. the output vo ltage can be set to any value between 1.24v (v ref ) to 18v with two external r e sistors as shown in the typical applic ation circuit. the device exhibit a wide operating current range of 0.2 to 100 ma with a typical dynamic impedance of 0.25 . active output circuitry provides a very sharp turn-on characteristic, making the L431L excellent re- placements for low-voltage zener diodes in many applications, including on- board regulat- ion and adjustable power supplies. when used with an opto- coupler , the L431L is ideal v o ltage reference in isolated feedback circuits for 3.3v switching-mode power supplies . the L431L shunt regulator is available in two voltage tolerances (0.5% & 1.0%) and three package options (t o-92, sot-23-3 and so-8). fea t ures z internal amplifier with 100 ma capability z programmable output voltage to 18v z 0.25 typical output impedance z pin to pin compatible with tl v431a, ts431, sc431l & as432 z t r immed bandgap design 0.5% & 1.0% with three package options z low output noise applica t ions z linear regulator controller z precision voltage reference z switching power supplies z battery operating equipment z instrumentation z pcs, computer disk drives symbol & block diagram anode (a) cathod reference - + cathode (k) anode (a) reference (r) 1.24 vref functional block diagram symbol (r) (k) apr-25-2002 www..net
2 1.24v low-voltage adjustable precision shunt regulator niko-sem L431L apr-25-2002 absolute maximum ratings parameter value cathode-anode reverse breakdown voltage - v ka 20v anode-cathode forward current - i ak 1 a operating cathode current - i ka 100 ma reference input current - i ref 1 ma storage temperature range - t stg -65 to +150 c junction temperature - t j 150 c lead temperature (soldering, 10 seconds) - t l 300 c continuous power at 25 c - p d to-92 soic-8 sot-23 700 mw 650 mw 200 mw recommended conditions typical thermal resistances parameter rating package ? ? ? ?
niko-sem L431L 3 1.24v low-v oltage adjustable precision shunt regulator test circuits in v v ka k i ref i v ref r1 r2 - test circuit 2 - > (v ka v ref ) ref i ) v ka v = - test circuit 1 - ka v ref (v in - test circuit 3 - ka vv in k (off) i (off state current) i k applications information ? stability selection of load capacitance w h e n u s i n g L431L as a shunt regulator when the L431L is used as a shunt regulator , two options for selection of cl are recommended for optimal stability: 1. no load capacitance across the device, decouple at the load. 2. large capacitance across the device, optional decoupling at the load. the reason for this is that L431L exhibits instability with capacitanc es in the range of 1nf to 1uf (approx.) at light cathode currents (up to 3ma typical). the device is less stable the lower the cathode voltage has been set for . therefore while the device will be perfectly stable operating at a ca thode current of 10ma with a 0.1uf capacitor across it, it will oscillate transiently during start-up as the cathode current passes through the instability region. selecting a very low (or preferably , no)capacitance, or alter- natively a high capacitance (such as 10uf) will avoid this issue altogether . since the user will probably wis h to have local decoupling at the load anyway , the most cost ef fective method is to use no capacitanc e at all directly across the device. pcb trace/via resistance and inductance prevent the local load de- coupling from causing the oscillation during the transient start-up phase. n o te : if the L431L is located right at the load, so the load dec ou pling c apac itor is direc t ly across it, then this capacit or will ha ve to be 100pf or
1uf . apr-25-2002
niko-sem L431L smal l - si g nal g a i n an d ph ase shi f t vs. freq ue ncy 4 1.24v low-v oltage adjustable precision shunt regulator apr-25-2002 st ab il ity bo un dar y con d it ion for s h u n t re gu la ti on vs. ca th od e cur r e n t a nd lo ad c a p a c i t a n c e vs . ca tho d e vo ltag e cathode current ca thod e cu rren t vs. cath ode voltag e 15 k 23 2 gn d 1 2 10 uf ou t 1 2 iz 8. 2 5 k test c i rcui t f o r s m al l s i gnal g a i n and p h as e l4 31 l 2 3 1 cl 1 2 r2 r1 r t e s t cir c u i t fo r s t a b il ity l4 31 l 2 3 1 iz
niko-sem L431L 5 1.24v low-v oltage adjustable precision shunt regulator apr-25-2002 vs. freq uenc y refere nce imp edan ce
niko-sem L431L 6 1.24v low-v oltage adjustable precision shunt regulator apr-25-2002 pin configura tions vs. j uncti on te mpe r ature r z ( ) reference imp e dance vs. j unctio n te mperature off-state cathode current
niko-sem L431L 7 1.24v low-v oltage adjustable precision shunt regulator device selection guide device l 4 3 1 l n b l 4 3 1 l m 3 b L431L v b l 4 3 1 l m 5 b package t o - 9 2 s o t - 2 3 - 3 s o i c - 8 s o t - 2 3 - 5 marking l 4 3 1 l n 1lm3 L431L v 1lm5 t o lerance 1 % 1 % 1 % 1 % applica t ion circuit + 10 uf + co u t + ci n p 0 1 n 02 l m or p 3 0 5 5 l l4 31 l r1 r2 1k 5 v or 12 v vi n vo u t g d s a k r ni k o ni k o v o u t = ( 1 + ) v r e f r2 r1 apr-25-2002
niko-sem L431L 8 1.24v low-v oltage adjustable precision shunt regulator apr-25-2002 t o -92 mechanical da t a mm mm dimension m i n . t y p . m a x . dimension m i n . t y p . m a x . a 4 . 4 4 5 5 . 2 0 7 h 2 . 4 1 3 2 . 5 4 0 2 . 6 6 7 b 4 . 3 1 8 5 . 3 3 4 i 0 . 3 5 6 0 . 5 3 3 c 1 2 . 7 1 5 . 5 j d 0 . 3 5 6 0 . 5 3 3 k e 1 . 1 4 3 1 . 2 7 1 . 3 9 7 l f 3 . 1 7 5 4 . 1 9 1 m g 0 . 7 6 2 1 . 2 7 0 n
niko-sem L431L 9 1.24v low-v oltage adjustable precision shunt regulator apr-25-2002 sot-23 (m3) mechanical da t a mm mm dimension m i n . t y p . m a x . dimension m i n . t y p . m a x . a 0 . 9 5 h 0 . 1 0 0 . 1 5 0 . 2 5 b 2 . 6 0 2 . 8 0 3 . 0 0 i 0 . 3 7 c 1 . 4 0 1 . 6 0 1 . 8 0 j d 2 . 7 0 2 . 9 0 3 . 1 0 k e 1 . 0 0 1 . 1 0 1 . 3 0 l f 0 . 0 0 0 . 1 0 m g 0 . 3 5 0 . 4 0 . 5 n
niko-sem L431L 10 1.24v low-v oltage adjustable precision shunt regulator apr-25-2002 soic-8 (d) mechanical da t a mm mm dimension m i n . t y p . m a x . dimension m i n . t y p . m a x . a 4 . 8 5 . 0 h 0 . 4 1 . 2 7 b 3 . 8 4 . 0 i 0 . 1 8 0 . 2 5 c 5 . 8 6 . 2 j 0 . 2 2 d 0 . 3 5 0 . 4 8 k 0 q 8 q e 1 . 2 7 l f 1 . 6 5 m g 0 . 1 0 . 2 5 n
niko-sem L431L 11 1.24v low-v oltage adjustable precision shunt regulator sot-23 (m5) mechanical da t a mm mm dimension m i n . t y p . m a x . dimension m i n . t y p . m a x . a 1 . 0 1 . 1 0 1 . 3 0 e 1 . 9 0 ( t y p ) a 1 0 . 0 0 0 . 1 0 h 2 . 6 0 2 . 8 0 3 . 0 0 a 2 0 . 7 0 0 . 8 0 0 . 9 0 l 0 . 3 7 b 0 . 3 5 0 . 4 0 0 . 5 0 c 0 . 1 0 0 . 1 5 0 . 2 5 d 2 . 7 0 2 . 9 0 3 . 1 0 e 1 . 4 0 1 . 6 0 1 . 8 0 apr-25-2002

▲Up To Search▲

Price & Availability of L431L

	To Download L431L Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .