?2003 fairchild semiconductor corporation www.fairchildsemi.com rev. 1.0.4 features ? programmable output voltage to 36 volts ? low dynamic output impedance 0.20 typical ? sink current capability of 1.0 to 100ma ? equivalent full-range temperature coefficient of 50ppm/ c typical ? temperature compensated for operation over full rated operating temperature range ? low output noise voltage ? fast turn-on response description the lm431sa/lm431sb/lm431sc are three terminal output adjustable regulators 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 external 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. sot-23f 1 2 3 1. cathode 2. ref 3. anode 1. ref 2. anode 3. cathode 1 sot-89 internal block diagram lm431sa/lm431sb/lm431sc programmable shunt regulator
lm431sa/lm431sb/lm431sc 2 absolute maximum ratings (operating temperature range applies 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 ambient temperature at 25 c 4. power dissipation calculation: p d = (t j - t a )/ r ja recommended operating 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) mf suffix package ml suffix package r ja 350 220 c/w power dissipation (note3,4) mf suffix package ml suffix package p d 350 560 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 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 - 4.5 17 - 4.5 17 - 4.5 17 mv ratio of change in reference input 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 to the change in cathode voltage ? 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 = -1.54 -1.54 -1.54 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 - 0.4 1.2 - 0.4 1.2 - 0.4 1.2 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 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 5 typical performance characteristics -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) -50 -25 0 25 50 75 100 125 0.000 0.025 0.050 0.075 0.100 i off , off-state cathode 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) -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 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) 048121620 0 1 2 3 4 5 6 t a =25 o c output input voltage swing (v) time (us) figure 4. cathode current vs. cathode voltage figure 5. cathode current vs. cathode voltage figure 6. off-state cathode current vs. ambient temperature figure7. reference input current vs. ambient temperature figure 8. small signal voltage amplification vs. frequency figure 9. pulse response
lm431sa/lm431sb/lm431sc 6 typical performance characteristics (continued) 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 figure 10. stability boundary conditions figure 11. anode-reference diode curve figure 12. reference-cathode diode curve 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 c urr ent(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 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-termianl fixed regulator figure 15. high current shunt regulator figure 16. current limit or current source figure 17. constant-current sink
lm431sa/lm431sb/lm431sc 8 mechanical dimensions package dimensions in millimeters marking sot-23f 43a 43b 43c 2% tolerance 1% tolerance 0.5% tolerance
lm431sa/lm431sb/lm431sc 9 mechanical dimensions (continued) package dimensions in millimeters marking sot-89 0.40 0.10 2.50 0.20 (0.50) (0.40) 4.10 0.20 0.40 +0.10 ?.05 0.50 0.10 1.65 0.10 4.50 0.20 1.50 0.20 c0.2 1.50 typ 1.50 typ (1.10) 43a 2% tolerance 1% tolerance 0.5% tolerance 43b 43c
lm431sa/lm431sb/lm431sc 8/4/03 0.0m 001 stock#dsxxxxxxxx ? 2003 fairchild semiconductor corporation life support policy fairchild?s products are not authorized for use as critical components in life support devices or systems without the express written approval of the president of fairchild semiconductor corporation. as used herein: 1. life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and (c) whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury of the user. 2. a critical component in any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. www.fairchildsemi.com disclaimer fairchild semiconductor reserves the right to make changes without further notice to any products herein to improve reliability, function or design. fairchild does not assume any liability arising out of the application or use of any product or circuit described herein; neither does it convey any license under its patent rights, nor the rights of others. ordering information product number output voltage tolerance package operating temperature lm431sccml 0.5% sot-89 -25 ~ +85 c lm431sccmf sot-23f lm431sbcml 1% sot-89 lm431sbcmf sot-23f lm431sacml 2% sot-89 lm431sacmf sot-23f
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