rev. 10/11/00 AS2431 micropower sot-23, 2.5v precision adjustable shunt regulator features applications ? voltage tolerance ............................................... 0.5% ? battery operating equipment ? wide operating current ..................... 1ma to 100ma ? adjustable supplies ? extended temperature range ............... 0 c to 105 c ? switching power supplies ? low temperature coefficient ........................30 ppm/ c ? error amplifiers ? offered in small low power sot-23 package ? single supply amplifier ? low output noise ? monitors / vcr / tv ? personal computers product description the AS2431 is a 3-terminal adjustable s hunt voltage regulator providing a highly accurate 0.5% bandgap reference. as 2431 acts as an open-loop error amplifier with a 2.5v temperature compensation reference. the AS2431 thermal stability, wide operating curre nt (100ma) and temperature range (105 c) makes it suitable for all variety of applications that are looking for a low cost solution with high performance. AS2431 tolerance of 0.5% is proven to be sufficient to overcome all of the other errors in the system to virtually eliminate the need for trimming in the power supply manufactures assembly line and contribute a significant cost savings. in the standard shunt configuration, the combination of low temperature coefficient (t.c.), sharp turn-on characteristics, low output impedance and programmable output voltage make this precision reference an excellent error amplifier. the AS2431 is a direct replacement for the as431 and tl431 in low voltage, low current applications. ordering information sot-23 5-pin sot-23 3-pin temp oper range AS2431ym5 AS2431ym 0 c to 105 c y = output accuracy (y= a or blank) sot-23 top view 0.5% device cathode AS2431 ref anode sot-23 top view 1% device cathode as2432 ref anode sot-23-5 3 2 1 top view 1% device n/c cathode as2432 ref anode 54 n/c sot-23-5 3 2 1 top view 0.5% device n/c cathode AS2431 ref anode 54 n/c pi n conn e c ti ons
rev. 10/11/00 AS2431 absolute maximum ratings parameter symbol rating units cathode-anode reverse breakdown v ka 18 v anode-cathode forward current i ak 1 a operating cathode current i ka 100 ma reference input current i ref 1 ma continuous power dissipation at 25 c, sot-23 p d 300 mw junction temperature t j 150 c storage temperature t stg - 65 to 150 c lead temperature (soldering 10 sec.) t l 300 c stresses greater than those listed under absolute maximum ratings may cause permanent damage to the device. this is a stress ra ting only and functional operation of the device at these or any other conditions above those indicated in the operational sections of this specificatio n is not implied. exposure to absolute maximum rating conditions for extended periods may affect reliability. recommended conditions typical thermal resistances parameter symbol rating unit package 0 ja 0 jc typical derating current voltage v ka v ref to 18 v sot-23 575 c/w 150 c/w 1.7 mw/ c cathode current i k 10 ma 2.5v + - reference (r) cathode (k) anode (a)
rev. 10/11/00 AS2431 electrical characteristics are guaranteed over full junction temperature range (0 c to 105 c). ambient temperature must be derated based on power dissipation and package thermal characteristics. the conditions are: v ka = v ref and i k = 10ma, unless otherwise specified. AS2431a AS2431 test parameter symbol test condition min typ max min typ max unit circuit reference voltage v ref t a = 25 c 2.487 2.500 2.513 2.474 2.500 2.526 v 1 over temp. 2.480 2.520 2.460 2.540 v 1 ? v ref with temp* tc 0.07 0.20 0.07 0.20 mv/ c 1 ratio of change in v ref ? v ref v ref to 10 v -2.7 -1.01 -2.7 -1.01 to cathode voltage ? v k 10 v to 18 v -2 -0.4 0.3 -2 -0.4 0.3 reference input current i ref 0.7 4 0.7 4 a 2 i ref temp deviation ? i ref 0.4 1.2 0.4 1.2 a 2 min i k for regulation i k (min) 0.4 1 0.4 1 ma 1 off state leakage i k (off) v ref = 0v v ka = 18v 0.04 500 0.04 500 na 3 dynamic output impedance z ka f < 1 khz i k = 1 to 100ma 0.15 0.5 0.15 0.5 ? 1 calculating average temperature coefficient (tc) mv/v 2 ppm mv tc in mv/c = ? v ref (mv) ? t a tc in %/c = v ref at 25c ? t a ? v ref ) ) x 100 tc in ppm/c = v ref at 25c ? t a ? v ref ) ) x 10 6 5000 ? -55 0.06 mv/c ? v ref 0 0 0 % -20 -10 0.5 temperature (c) 0.002 %/c 24 ppm/c -25 0 25 50 75 100 125
rev. 10/11/00 AS2431 test circuits i k i ref v in v ka = v ref v in v ka i k r 1 r 2 (v ref ) figure 1b. test circuit 2 figure 1a. test circuit 1 v in v ka i k (off) figure 1c. test circuit 3
rev. 10/11/00 AS2431 typical performance curves v r ef - reference voltage (v) v ka - cathode voltage (v) high current operating characteristics figure 3 -2-10123 -100 -75 -50 -25 0 25 50 75 100 125 150 i k - cathode current (ma) v ka = v ref temperature range: - 0 to 105 c figure 4 off state leakage -60 -30 0 30 60 90 120 0.01 0.1 1 10 100 t a - ambient temperature ( c) i z off - off state cathode current (na) v ka = 18v v ref = 0v figure 5 t a - ambient temperature ( c) 90 120 reference voltage vs. ambient temperature -60 -30 0 30 60 2.45 2.46 2.47 2.48 2.49 2.50 2.51 2.52 2.53 v ka = v ref i k = 10 ma v ref = 2.500 v at 25 c figure 2 low current operating characteristics v ka - cathode voltage (v) 900 800 700 600 500 400 300 200 100 0 -100 -200 1.0 -1.0 2.0 0 3.0 i k - cathode current ( a) v ka = v ref temperature range: - 0 to 105 c 105 c 25 c -0c
rev. 10/11/00 AS2431 typical performance curves figure 8 f - frequency (hz) noise voltage nv/ hz 20 10 10 100 1 k 10 k 100 k 0 noise voltage 70 30 40 50 60 v ka = v ref i k = 10 ma t a = 25c t a - free air temperature figure 9 low frequency dynamic output impedance z k a - dynamic impedance ( ? ? ? ? ) -60 -30 0 30 60 90 120 0.0 v ka = v ref i ka = 1 to 100 ma f < 1 khz 0.025 0.050 0.075 0.100 0.125 0.150 figure 7 reference voltage line regulation v ka - cathode voltage (v) v ref - change in reference voltage (mv) 0 -10 -20 -30 -40 -50 t a - ambient temperature ( c) figure 6 reference input current i r ef - reference input current ( a) -60 -30 0 30 60 90 120 0 r1 = 10 k ? r2 = i k = 10 ma 0.5 1.0 1.5 2.0 2.5 3.0 18 0 3 6 9 12 15 105 c 75 c 25 c 0 c
rev. 10/11/00 AS2431 typical performance curve figure 11 10 m dynamic output impedance figure 10 f - frequency (hz) z ka - dynamic impedance 100 0.1 1.0 10 1 k 10 k 100 k 1 m 0.01 t a = 25 c i k = 1 to 100 ma 9 f 15 k 8.25 k gnd out 230 ? i k small signal voltage gain vs. frequency f - frequency (hz) a v - small signal voltage gain (db) 70 20 30 40 10 50 60 1 k 10 k 100 k 1 m 10 m 0 temperature range: -0 to 105 c i k = 10 ma
rev. 10/11/00 AS2431 typical performance curves out gnd 220 ? f p = 100 khz input monitor 50 ? pulse response figure 12 t - time ( s) input and output voltages (v) 12 -1 0 1 2 3 4 5 6 11 10 9 8 7 6 5 4 3 2 1 0 150 ? 10 k i k c l stability boundary conditions figure 13 c l - load capacitance (pf) i k - cathode current (ma) output 10 7 10 6 10 5 10 4 10 3 10 2 10 1 10 0 0 10 20 30 40 50 60 70 80 90 100 stability region t a = 25 c a: v ka = v ref b: v ka = 5v at i k = 10 ma c: v ka = 10v at i k = 10 ma d: v ka = 15v at i k = 10 ma d c a b input
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