smps controller ?2000 fairchild semiconductor corporation www.fairchildsemi.com rev. 1.0.0 features ? low start current 0.2ma (typ.) operating range up to 500khz cycle by cycle current limiting under voltage lock out with hysteresis short shutdown delay time: typ. 100ns high current totem-pole output output swing limiting: 22v description the ka3882c/3c are fixed pwm controller for off-line and dc to dc converter applications. the internal circuits include uvlo, low start up current circuit, temperature compensated reference, high gain error amplifier, current sensing comparator, and high current totem-pole output for driving a power mosfet. also ka 3882c/3c provide low start up current below 0.3ma and short shutdown delay time typ. 100ns. the ka3882c has uvlo threshold of 16v(on) and 10v(off). the ka3883 is 8.4v(on) and 7.6v(off). the ka3882 and ka3883 can operate within 100% duty cycle. 8 dip 8 sop ka3882c/3c current mode pwm controller
ka3882c/3c 2 smps controller internal block diagram 8 + - 7 5 set/ reset 5v v ref internal bias good logic 2 r s oscillator 1 3 4 t 7 6 5 uvlo 29v 22v 1/3 error amp 1/2v ref 1v c.s comp. pwm latch v ref v fb comp c.s r t /c t output v cc gnd pwr v c pwr gnd
ka3882c/3c 3 smps controller absolute maximum rating electrical characteristics (v cc =15v, r t =10k ? , c t =3.3nf, ta=0 c ~ +85 c, unless otherwise specified) parameter symbol value unit supply voltage v cc 30 v output current i o +1 a analog inputs (pin2, 3) v i(ana) -0.3 ~ 6.3 v error amp. output sink current i sink(ea) 10 ma power dissipation p d 1w parameter symbol conditions min. typ. max. unit reference section output voltage v ref t j =25 c , i o =1ma 4.9 5.0 5.1 v line regulation ? v ref v cc =12v to 25v - 6 20 mv load regulation ? v ref i o =1ma to 20ma - 6 25 mv output short circuit i sc ta=25 c - -100 -180 ma osillator section initial accuracy f osc t j =25 c475257khz voltage stability st v v cc =12v to 25v - 0.2 1 % amplitude v osc v pin4 , peak to peak - 1.7 - v discharge current i dischg t j =25 c , pin4=2v 7.8 8.3 8.8 ma current sense section gain note2, 3 g v - 2.85 3 3.15 v/v maximum input signal note2 v i(max) v pin1 =5v 0.9 1.0 1.1 v psrr note1, 2 psrr v cc =12v to 25v - 70 - db input bias current i bias ---2-10 a delay to output note1 t d v pin3 =0v to 2v - 100 200 ns error amplifier section input voltage v i t pin1 =2.5v 2.42 2.50 2.58 v input bias current i bias - - -0.3 -2 a open loop gain note1 gv o v o =2v to 4v 65 90 - db unity gain bandwidth note1 gbw t j =25 c0.71-mhz psrr note1 psrr v cc =12v to 25v 60 70 - db output sink current i sink v pin2 =2.7v, v pin1 =1.1v 2 6 - ma output source current i source v pin2 =2.3v, v pin1 =5.0v -0.5 -0.8 - ma output high voltage v oh v pin2 =2.3v, r1=15k ? to gnd 5 6 - v output low voltage v ol v pin2 =2.7v, r1=15k ? to pin8 - 0.8 1.1 v
ka3882c/3c 4 smps controller electrical characteristics (continued) (v cc =15v, r t =10k ? , c t =3.3nf, ta=0 c ~ +85 c, unless otherwise specified) adjust vcc above the start threshold before setting at 15v notes; 1. these parameters, although guaranteed, are not 100% tested in production. 2. parameter measured at trip point of latch with v2=0v. 3. gain defined as: g v = ? v pin1 ? v pin3 (v pin3 =0v to 0.8v) parameter symbol conditions min. typ. max. unit output section output low level v ol i sink =20ma - 0.1 0.4 v i sink =200ma - 1.5 2.2 v output high level v oh i source =20ma 13 13.5 - v i source =200ma 12 13.5 - v rise time note1 t r t j =25 c, c1=1nf - 40 100 v fall time note1 t f t j =25 c, c1=1nf - 40 100 ns output voltage swing limit v olim v cc =27v, c1=1nf - 22 - ns under voltage lockout section start threshold v th ka3882c 15 16 17 v ka3883c 7.8 8.4 9.0 v min. operating voltage (after turn on) v tl ka3882c 9 10 11 v ka3883c 7.0 7.6 8.2 v pwm section maximum duty cycle d max ka3882/3 94 -96 100 v minimum duty cycle d min ---0v total standby current start-up current i st --0.20.4ma operating supply current i cc v pin2 =v pin3 =0v - 11 17 ma v cc zener voltage v z i cc =25ma - 29 - v
ka3882c/3c 5 smps controller ordering information device package operating temperature ka388x 8 dip 0 ~ +85 c ka388dx 8 sop
ka3882c/3c 6 smps controller
ka3882c/3c 7 smps controller
ka3882c/3c smps controller 12/17/99 0.0m 001 stock#dsxxxxxxxx ? 1999 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
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