description the gs431b/tl431a/tl431 are 3-terminal adjustable precision shunt regulators with guaranteed temperature stability over the applicable extended commercial temperature range. the output voltage may be set at any level greater than 2.495v (v ref ) up to 30v merely by selecting two external resistors that act as a voltage divider network. these devices have a typical output impedance of 0.08 ? . active output circuitry provides very sharp turn-on characteristics, making these devices excellent improved replacements for zener diodes in many applications. the precise ?.5% reference voltage tolerance of the gs431b makes it possible in many applications to avoid the use of a variable resistor, consequently saving cost and eliminating drift and reliability problems associated with it. applications ?voltage monitor ?delay timer ?constant-current source/sink ?high-current shunt regulator ?crow bar ?over-voltage/under-voltage protection mechanical data case: so-8, sot-23, sot-89, to-92 high temperature soldering guaranteed: 260?/10 seconds at terminals case outlines are on the back pages features ?programmable output voltage to 30v ?precision reference voltage gs431b: 2.495v ?.5% tl431a: 2.495v ?.0% tl431: 2.495v ?.6% ?sink current capability: 200ma. ?minimum cathode current for regulation: 250 a ?equivalent full-range temperature coefficient: 50 ppm/ c ?fast turn-on response ?low dynamic output impedance: 0.08 ? ?low output noise to-92 lp suffix u suffix sot-23 s suffix so-8 x suffix sot-89 1 2 3 1 2 3 symbol block diagram a node (a) ref (r) cathode (c) ref (r) + - anode (a) cathode (c) 2.495v 1 2 3 4 8 7 6 5 1 2 3 gs431b/tl431a/tl431 vishay formerly general semiconductor preliminary adjustable precision shunt regulators document number 74806 www.vishay.com 1-jul-02 1
ordering information GS431BIxx package code so-8: s to-92: lp sot-89: x sot-23: u-1/u-2 u-1: pin 1, cathode pin 2, v ref pin 3, anode u-2: pin 1, v ref pin 2, cathode pin 3, anode tolerance default: 1.6% tl431xixx a: 1.0% package code so-8: s to-92: lp sot-89: x sot-23: u-1/u-2 1 2 3 1 2 3 4 8 7 6 5 1 2 3 1 2 3 top view 1. cathode 2. v ref 3. anode cathode anode anode nc ref anode anode nc 1 2 3 top view 1. v ref 2. cathode 3. anode top view 1. v ref 2. anode (tab) 3. cathode top view 1. v ref 2. anode 3. cathode top view so-8 sot-23 (u-1) sot-23 (u-2) sot-89 to-92 marking information sot-23 gs431b, (u-1) daxxxx * tl431a, (u-1) dbxxxx tl431, (u-1) dcxxxx gs431b, (u-2) ddxxxx tl431a, (u-2) dexxxx tl431, (u-2) dgxxxx * last two digits denote datecode gs431b/tl431a/tl431 vishay formerly general semiconductor www.vishay.com document number 74806 2 1-jul-02
electrical characteristics t a = 25 c unless otherwise noted. parameter symbol t est conditions min typ max unit v z = v ref gs431b 2.482 2.495 2.508 i l = 10ma (fig. 1) tl431a 2.470 2.495 2.520 reference voltage v ref t a = 25 c tl431 2.455 2.495 2.535 v v z = v ref gs431b 2.475 2.520 i l = 10ma (fig. 1) tl431a 2.445 2.545 t a = 40 c to +85 c tl431 2.43 2.56 deviation of reference ? v ref v z = v ref t a = 0 c to 70 c 9.0 20 mv input voltage over temperature (1) i l = 10ma t a = 40 c to +85 c (fig. 1) 15.0 50 ratio of the change in reference voltage ? v ref i z = 10ma v z = v ref ~ 10v 0.5 2.0 mv/v to the change in cathode voltage ? v z (fig. 2) v z = 10v ~ 30v 0.35 1.5 reference input current i ref r1 = 10k ? , r2 = t a = 25 c 0.8 3.5 a i l = 10ma (fig. 2) t a = 40 c to +85 c 4.5 deviation of reference input r1 = 10k ? , r2 = current over temperature i ref i l = 10ma 0.3 1.2 a t a = 40 c to +85 c (fig. 2) minimum cathode current i z(min) v z = v ref (fig. 1) 0.25 0.5 ma for regulation off-state current i z(off) v z = 30v, v ref = 0v (fig 3) 0.1 1.0 a dynamic output impedance (2) r z v z = v ref , f = 1.0kh z 0.08 0.3 ? ? iz = 1.0ma to 50ma absolute maximum ratings t a = 25 c unless otherwise noted. parameter symbol value unit cathode voltage v z 30 v continuous cathode current i z 10 to 250 ma reference input current range i ref 0.05 to10 ma operating temperature range t oper 40 to 85 c junction temperature t j 150 c lead temperature t l 260 c storage temperature tstg 65 to 150 c thermal resistance to-92 package 115 sot-23 package r ja 310 c/w so-8 package 163 sot-89 package 120 gs431b/tl431a/tl431 vishay formerly general semiconductor document number 74806 www.vishay.com 1-jul-02 3
t 2 t temperature 1 v max min v dev = v max min -v v the average temperature coefficient of the reference input voltage, v ref is defined as: t1 t2 10 6 c) 25 (at v v t1 t2 10 6 c) 25 (at v v - v c ppm v ref dev ref min max ref = = where: t 2 t 1 = full temperature change. the slope can be positive or negative depending on whether v max or v min occurs at the lower ambient temperature. example: ? v ref = 9.0mv, v ref = 2495mv, t 2 - t 1 = 70 c, slope is positive. c 50ppm/ v ref = c 70 10 6 2495mv 9.0mv = note 2. the dynamic output impedance, r z , is defined as: when the device is programmed with two external resistors, r1 and r2, (see fig. 2), the dynamic output impedance of the overall circuit, is defined as: z ? v z r = ? z i r2 r1 1 r z i z v z z r + ? ? = note 1. deviation of reference input voltage, ? v ref , is defined as the maximum variation of the reference input voltage over the full temperature range. v ref i ref i z v z i l in r2 r1 v ref i ref i z v z in i l note: v z =v ref (1+r1/r2)+i ref xr1 in v z i z(off) fff c fig. 1 test circuit for v z =v ref fig. 2 test circuit for v z >v ref fig. 3 test circuit for off-state current gs431b/tl431a/tl431 vishay formerly general semiconductor www.vishay.com document number 74806 4 1-jul-02
document number 74806 www.vishay.com 1-jul-02 5 1.15 1.10 1.05 1.00 0.95 0.90 0.85 0.80 0.75 0.70 1.20 fig. 6 ?reference input current vs. temperature reference input current ( a) temperature ( c) -40 -20 0 20 40 60 80 100 120 --40 --20 0 20 40 60 80 100 120 r1=10k ? r2= i z =10ma i z =10ma t a =25 c v z = v ref i z = 1ma to 100ma f 1kh z v z =v ref v z =30v 0.28 0.24 0.20 0.16 0.12 0.08 0.04 0.00 fig. 7 ?dynamic impedance vs. temperature dynamic impedance ( ? ) temperature ( c) 5 101520253035 40 fig. 8 ?change in reference voltage vs. cathode voltage change in reference voltage (mv) cathode voltage (v) --12 --10 -- 8 -- 6 -- 4 -- 2 0 0 2.5 2.0 1.5 1.0 0.5 0.0 --40 0 60 40 20 -20 80 100 120 fig. 9 ?off-state cathode current vs. temperature off-state cathode current ( a) temperature ( c) 1000 800 600 400 200 0 -200 -400 -800 fig. 4 ?cathode current vs. cathode voltage fig. 5 ?reference voltage vs. temperature cathode current ( a) 2.58 2.56 2.54 2.52 2.50 2.48 2.46 2.44 2.42 2.40 reference voltage (v) cathode voltage (v) temperature ( c) -1.0 -0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 -40 -20 0 20 40 60 80 100 120 v z = v ref t a = 25 c tl431 v z = v ref i z = 10ma i z(min) v ref max v ref typ v ref min typical performance characteristics gs431b/tl431a/tl431 vishay formerly general semiconductor
0 1 2 3 2 4 6 0 fig. 12 pulse response fig. 13 test circuit for pulse fig. 15 test circuit for dynamic 1 s/div 0.1 1 10 1k 10k 100k 1m fig. 14 dynamic impedance vs. dynamic impedance ( ? ) (v) frequency (h z ) ra 50 ? rb 220 ? 431 output pulse generator f=100khz r1 50 + ac 1v r2 50 431 gnd output i z =10ma t a =25 c input output r1 10k r 250 + v in c in 47 f v1 431 output i z =10ma t a =25 c a v 0 10 20 30 40 50 60 70 80 10 100 1k 10k 100k 1m 10m fig. 10 small signal voltage amplification vs. frequency fig. 11 test circuit frequency response small-signal voltage amplification frequency (h z ) -- 1 0 gs431b/tl431a/tl431 vishay formerly general semiconductor www.vishay.com document number 74806 6 1-jul-02
fig. 17 delay timer fig. 18 voltage monitor fig. 16 typical application circuit fig. 20 current limiter or current source fig. 19 constant-current sink v in r1a r2a r1b r2b r on off c v in + n ( v vv in in ref ) r 1 i out v in r v in 1 i out i out =v ref / r 1 i out =v ref / r 1 led on when low limit v out r1 r2 v in v in r1 r2 v out fuse r1a r2a r2b r1b v in output on when low limit 5 123 4 6.20 5.80 87 6 4.00 3.80 0.51 0.33 1.27 (typ.) 0.25 0.10 5.00 4.80 1.75 1.35 1.27 0.40 0.25 0.19 so-8 case outline dimensions in millimeters 0.10 1 2 3 top view 3.10 2.70 3.00 2.60 1.80 1.40 0.90 0.70 1.90 (typ.) 0.25 0.10 0.50 0.35 1.30 1.00 0.37 1 9 1 sot-23 case outline dimensions in millimeters gs431b/tl431a/tl431 vishay formerly general semiconductor document number 74806 www.vishay.com 1-jul-02 9
to-92 case outline dimensions in millimeters 5.33 4.32 1.27 (typ.) bottom view 12.7 0.38 (typ.) 5.20 4.40 4.20 3.17 sot-89 case outline 1.83 1.62 1.60 1.40 4.60 4.40 top view 4.25 3.94 2.60 2.29 1.20 0.89 3.00 (typ.) 1.50 (typ.) 0.48 0.36 0.44 0.35 12 3 dimensions in millimeters gs431b/tl431a/tl431 vishay formerly general semiconductor www.vishay.com document number 74806 10 1-jul-02
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