1 52 khz 3a step-down switching voltage regulator (svr) n2576 to-263, to220 may-31-2001 niko-sem general description the n2576 series switching voltage regulators (svr) are monolithic integrated circuits that provide all the active functions for a step-down (buck) switching regulator, both series are capable of driving 3 a load respectively with excellent line and load regulation. the n2576 series svr include a switching regulator and compensation network all within the same package. just add a choke, catch diode and two capacitors to obtain an efficient dc-to-dc converter. the output switch includes cycle-by-cycle current limit -ing, as well as thermal shutdown for full protection under fault conditions. the n2576 series svr offer replacement for popular 3 terminal linear regulators by providing higher efficiency with reduced heat sink size. in many applications a heat sink will not be required. features z pin compatible with industry products of lm2576 series z adjustable output versions z wide output voltage range, 1.23v to 27v for adjustable output version z dc-to-dc buck converter requiring only 4 external parts z 52 khz fixed frequency internal oscillator z ttl shutdown capability, low power stand -by mode z high efficiency z uses readily available standard inductors applications z simple high-efficiency step-down (buck) regulator z positive to negative converter (inverting buck-boost) z isolated fly back converter using mini- mum number of external parts z powering portable instrument, set-top box, lcd monitor, scanner, i.a, easy pc z smps post-regulator typical application * v out = 1.23v ( 1 + r1 / r2) adjustable regulator in fixed output application + + cin d1 l1 r1 r2 cout n2576 1 2 3 4 +vin output gnd feedback 5 on/of f 8v - 27v dc input unregulated 100uf 1n5822 100uh 1000uf 2k 6.18k output +5v, 3a regulated
2 52 khz 3a step-down switching voltage regulator (svr) n2576 to-263, to220 may-31-2001 niko-sem absolute maximum ratings z maximum supply voltage 30v z on/off pin input voltage -0.3 v +v i z thermal resistance junction to ambient, ja to-220 to-263 50c/w 60c/w z output voltage to ground (stead state) -1v z operating junction temperature range -40 to 125c z power dissipation internally limited z storage temperature range -65 to 150c z thermal resistance junction to case, jc 2.0c/w z lead temperature (soldering, 10 seconds) 260c electrical characteristics ( unless otherwise specified, t a = 25c.) parameter symbol test conditions typical limits feedback voltage v out v in = 12v, v out = 5v i load = 0.5a (n2576) 1.230v 1.217v min 1.243v max feedback voltage v out 8v v in 27v 0.5a i load 3a (n2576) 1.230v 1.193v min 1.267v max efficiency v in = 12v, v out = 5v i out = 3a (n2576) 77% feedback bias current i b v out = 5v 50na 100na oscillator frequency f osc 52 khz 47 khz (min) 58 khz (max) saturation voltage v sat i out = 3a (n2576) 1.4v 1.8v max current limit i cl n2576 6.0a 4.0a ~ 7.0a v ih v out = 0v 1.4v 2.2v (min) on/off pin logic input level v il v out = nominal output voltage 1.2v 1.0v (max) i ih on/off pin = 5v (off) 12 a 30 a (max) on/off pin logic input current i il on/off pin = 0v (on) 0 a 10 a (max) device selection guide device N2576S N2576S-3.3 N2576S-5 n2576t n2576t-3.3 n2576t-5 voltage (v) adj 3.3 5 adj 3.3 5 current (a) 3 package to-263 to-263 to-263 to-220 to-220 to-220
3 52 khz 3a step-down switching voltage regulator (svr) n2576 to-263, to220 may-31-2001 niko-sem pin configurations 5 - on/off 4 - feedback 3 - ground 1 - vin 2 - output ground ground 2 - output 1 - vin 3 - ground 4 - feedback 5 - on/off 5 -lead to-220 (t) 5 -lead to-263 (s)
4 52 khz 3a step-down switching voltage regulator (svr) n2576 to-263, to220 may-31-2001 niko-sem to-220 (5-lead) mechanical data mm mm dimension min. typ. max. dimension min. typ. max. a 9.78 10.16 10.54 h 1.57 1.7 1.83 b 2.61 2.74 2.87 i 6.81 c j 4.4 4.6 4.8 d 28.5 28.9 29.3 k 1.14 1.27 1.4 e 14.6 15.0 15.4 l 2.3 2.6 2.9 f 8.4 8.8 9.2 m 0.26 0.46 0.66 g 0.73 0.83 0.93 n 7
5 52 khz 3a step-down switching voltage regulator (svr) n2576 to-263, to220 may-31-2001 niko-sem to-263 (d 2 pak, 5-lead) mechanical data mm mm dimension min. typ. max. dimension min. typ. max. a 14.5 15 15.8 h 1.0 1.5 1.8 b 4.2 4.7 i 9.8 10.3 c 1.20 1.35 j 6.5 d 2.8 k 1.5 e 0.3 0.4 0.5 l 0.7 0.85 1.0 f -0.102 0.203 m 1.57 1.7 1.83 g 8.5 9 9.5 n
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