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lm431sa/lm431sb/lm431sc ? pr ogrammable shunt regulator ? 2012 fairchild semiconductor corporation www.fairchildsemi.com lm431sa/lm431sb/lm431sc rev. 1.2.0 1 june 2012 lm431sa/lm431sb/lm431sc programmable shunt regulator features ? programmable output voltage to 36 volts ? low dynamic output impedance 0.2 typical ? sink current capability of 1.0 to 100ma ? equivalent full-range te mperature coefficient of 50ppm/ c typical ? temperature compensated for operation over full rated operating temperature range ? low output noise voltage ? fast turn-on response internal block diagram 1. ref 2. anode 3. cathode 1 sot-89 sot-23f 1 2 3 1. cathode 2. ref 3. anode sot-23 1 2 3 m32 - 1. ref 2. cathode 3. anode m3 - 1. cathode 2. ref 3. anode + - description the lm431sa/lm431sb/lm431sc are three terminal output adjustable regulator s with thermal stability over operating temperature range . the output voltage can be set any value between v ref (approximately 2.5 volts) and 36 volts with two extern al resistors. these devices have a typical dynamic output impedance of 0.2 . active output circuit provides a sharp turn-on characteristic, making these devices excellent replacement for zener diodes in many applications.
lm431sa/lm431sb/lm431sc ? pr ogrammable shunt regulator ? 2012 fairchild semiconductor corporation www.fairchildsemi.com lm431sa/lm431sb/lm431sc rev. 1.2.0 2 absolute maximum ratings (operating temperature range app lies unless otherwise specified.) note: 1. thermal resistance test board size: 76.2mm * 114.3mm * 1.6mm (1s0p) jedec standard: jesd51-3, jesd51-7 2. assume no ambient airflow. 3. t jmax = 150 c, ratings apply to am bient temperature at 25 c 4. power dissipation calculation: p d = (t j - t a )/r ja recommended oper ating conditions parameter symbol value unit cathode voltage v ka 37 v cathode current range (continuous) i ka -100 ~ +150 ma reference input current range i ref -0.05 ~ +10 ma thermal resistance junction-air (note1,2) ml suffix package (sot-89) mf suffix package (sot-23f) m32, m3 suffix package (sot-23) r ja 220 350 400 c/w power dissipation (note3,4) ml suffix package (sot-89) mf suffix package (sot-23f) m32, m3 suffix package (sot-23) p d 560 350 310 mw junction temperature t j 150 c operating temperature range t opr -25 ~ +85 c storage temperature range t stg -65 ~ +150 c parameter symbol min. typ. max. unit cathode voltage v ka v ref -36v cathode current i ka 1.0 - 100 ma lm431sa/lm431sb/lm431sc ? pr ogrammable shunt regulator ? 2012 fairchild semiconductor corporation www.fairchildsemi.com lm431sa/lm431sb/lm431sc rev. 1.2.0 3 electrical characteristics (t a = +25 c, unless otherwise specified) note1 t min = -25 c, t max = +85 c parameter symbol conditions lm431sa lm431sb lm431sc unit min. typ. max. min. typ. max. min. typ. max. reference input voltage v ref v ka =v ref , i ka =10ma 2.450 2.500 2.550 2.470 2.495 2.520 2.482 2.495 2.508 v deviation of reference input voltage over- temperature v ref / t v ka =v ref , i ka =10ma t min t a t max sot-89 sot-23f - 4.5 17 - 4.5 17 - 4.5 17 mv sot-23 - 6.6 24 - 6.6 24 - 6.6 24 mv ratio of change in reference input voltage to the change in cathode voltage v ref / v ka i ka =10ma v ka =10v -v ref - -1.0 -2.7 - -1.0 -2.7 - -1.0 -2.7 mv/v v ka =36v -10v - -0.5 -2.0 - -0.5 -2.0 - -0.5 -2.0 reference input current i ref i ka =10ma, r 1 =10k ,r 2 = - 1.5 4 - 1.5 4 - 1.5 4 a deviation of reference input current over full temperature range i ref / t i ka =10ma, r 1 =10k , r 2 = , t a =full range sot-89 sot-23f - 0.4 1.2 - 0.4 1.2 - 0.4 1.2 a sot-23 - 0.8 2.0 - 0.8 2.0 - 0.8 2.0 a minimum cathode current for regulation i ka(min) v ka =v ref - 0.45 1.0 - 0.45 1.0 - 0.45 1.0 ma off -stage cathode current i ka(off) v ka =36v, v ref =0 - 0.05 1.0 - 0.05 1.0 - 0.05 1.0 a dynamic impedance z ka v ka =v ref , i ka =1 to 100ma , f 1.0khz - 0.15 0.5 - 0.15 0.5 - 0.15 0.5 lm431sa/lm431sb/lm431sc ? pr ogrammable shunt regulator ? 2012 fairchild semiconductor corporation www.fairchildsemi.com lm431sa/lm431sb/lm431sc rev. 1.2.0 4 test circuits figure 1. test circuit for v ka =v ref figure 2. test circuit for v ka v ref lm431s lm431s lm431s figure 3. test circuit for l ka(off) lm431sa/lm431sb/lm431sc ? pr ogrammable shunt regulator ? 2012 fairchild semiconductor corporation www.fairchildsemi.com lm431sa/lm431sb/lm431sc rev. 1.2.0 5 typical performance characteristics figure 4. cathode current vs. cathode voltage f igure 5. cathode current vs. cathode voltage figure 6. off-state cathode current vs. ambient temperature figure 7. reference input current vs. ambient temperature figure 8. small signal voltage amplification vs. frequency figure 9. pulse response -2-10123 -100 -50 0 50 100 150 v ka = v ref t a = 25 o c i k , cathode current (ma) v ka , cathode voltage (v) -10123 -200 0 200 400 600 800 i ka(min) v ka = v ref t a = 25 o c i ka , cathode current (ua) v ka , cathode voltage (v) -50 -25 0 25 50 75 100 125 150 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20 i off , off-state cathode current (ua) t a , ambient temperature ( o c) -50 -25 0 25 50 75 100 125 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 i ref , reference input current (ua) t a , ambient temperature ( o c) 1k 10k 100k 1m 10m -10 0 10 20 30 40 50 60 t a = 25 o c i ka = 10ma open loop voltage gain (db) frequency (hz) 0 4 8 121620 0 1 2 3 4 5 6 t a =25 o c output input voltage swing (v) time (us) lm431sa/lm431sb/lm431sc ? pr ogrammable shunt regulator ? 2012 fairchild semiconductor corporation www.fairchildsemi.com lm431sa/lm431sb/lm431sc rev. 1.2.0 6 typical performan ce characteristics (continued) figure 10. stability boundary conditions figure 11. anode-reference diode curve figure 12. reference-cathode diode curve 100p 1n 10n 100n 1 10 0 20 40 60 80 100 120 140 b a a v ka = vref b v ka = 5.0 v @ i k = 10 ma t a = 25 o c i k , cathode current(ma) c l , load capacitance stable stable 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 0 1 2 3 4 5 current(ma) anode-ref. voltage(v) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 0 1 2 3 4 5 current(ma) ref.-cathode voltage(v) lm431sa/lm431sb/lm431sc ? pr ogrammable shunt regulator ? 2012 fairchild semiconductor corporation www.fairchildsemi.com lm431sa/lm431sb/lm431sc rev. 1.2.0 7 typical application v o 1 r 1 r 2 ------ - + ?? ?? v ref = lm431s v o v ref 1 r 1 r 2 ------ - + ?? ?? = lm431s lm7805/mc7805 v o 1 r 1 r 2 ------ - + ?? ?? v ref = lm431s lm431s lm431s figure 13. shunt regulator figure 14 . output control for three-terminal fixed regulator figure 15. high current shunt regulator figure 16. current limit or current source figure 17. constant-current sink lm431sa/lm431sb/lm431sc ? pr ogrammable shunt regulator ? 2012 fairchild semiconductor corporation www.fairchildsemi.com lm431sa/lm431sb/lm431sc rev. 1.2.0 8 mechanical dimensions package dimensions in millimeters marking 0 , 1 ? ; 0 , 1 0 , 1 0 , 1 0 , 1 ; 0 , 1 ? & ; & & & & ? ; 0 & $ % $ % & 6 ( $ 7 , 1 * 3 / $ 1 ( & & 1 2 7 ( 6 8 1 / ( 6 6 2 7 + ( 5 : , 6 ( 6 3 ( & |