?2006 fairchild semiconductor corporation 1 www.fairchildsemi.com march 2006 ka3842ac/KA3842AE rev. 1.0.1 ka3842ac/KA3842AE smps controller ka3842ac/KA3842AE smps controller features ? low start current 0.2ma (typ.) ? operating range up to 500khz ? cycle by cycle current limiting ? under voltage lock out (uvlo) with hysteresis ? short shutdown delay time: typ.100ns ? high current totem-pole output ? output swing limiting: 22v description the ka3842ac/KA3842AE are fixed pwm controllers for off line and dc to dc converter applications. the internal circuits include uvlo, low start up current, tem- perature compensated reference, high gain error ampli- fier, current sensing comparator, and high current totem pole output for driving a power mosfet. also ka3842ac/KA3842AE provides low start up current below 0.3ma and short shutdown delay time, typically 100ns. the ka3842ac/KA3842AE has a uvlo thresh- old of 16v(on) and 10v(off). the ka3842ac/KA3842AE can operate within a 100% duty cycle. ordering information part number operating temp. range pb-free package packing method ka3842ac -0 to +70c yes 8-dip tube KA3842AE 1 8-dip
2 www.fairchildsemi.com ka3842ac/KA3842AE rev. 1.0.1 ka3842ac/KA3842AE smps controller internal block diagram 8 + - 7 5 internal bias 5v v ref set/ reset good logic 2 r s oscillator 1 3 4 t 7 6 5 uvlo 29v 22v 1/3 error amp 1/2 v 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
3 www.fairchildsemi.com ka3842ac/KA3842AE rev. 1.0.1 ka3842ac/KA3842AE smps controller absolute maximum ratings the ?absolute maximum ratings? are those values beyon d which the safety of t he device cannot be guaranteed. the device should not be operated at t hese limits. the parametric values defined in the electrical characteristics tables are not guaranteed at the absolute maximum ra tings. the ?recommended operating conditions? table will define the conditions for actual device operation. symbol parameter value unit v cc supply voltage 30 v i o output current 1 a v i(ana) analog inputs (pins 2, 3) -0.3 to 6.3 v i sink(ea) error amp. output sink current 10 ma p d power dissipation 1 w r ja thermal resistance, junction-to-air (4) 95 c/w electrical characteristics (v cc = 15v, r t = 10k?, c t = 3.3nf, t a = 0c to +70c, unless otherwise specified) symbol parameter conditions min. typ. max. unit reference section v ref output voltage t j = 25c, i o = 1ma 4.9 5.0 5.1 v v ref line regulation v cc = 12v to 25v ? 6 20 mv load regulation i o = 1ma to 20ma ? 6 25 mv i sc output short circuit t a = 25c ? -100 -180 ma osillator section f osc initial accuracy t j = 25c 47 52 57 khz st v voltage stability v cc = 12v to 25v ? 0.2 1 % v osc amplitude v pin4 , peak to peak ? 1.7 ? v i dischg discharge current t j = 25c, pin 4 = 2v 7.8 8.3 8.8 ma current sense section g v gain (2)(3) 2.85 3 3.15 v/v v i(max) maximum input signal (2) v pin1 = 5v 0.9 1.0 1.1 v psrr psrr (1)(2) v cc = 12v to 25v ? 70 ? db i bias input bias current ? -2 -10 a t d delay to output (1) v pin3 = 0 v to 2v ? 100 200 ns error amplifier section v i input voltage t pin1 = 2.5v 2.42 2.50 2.58 v i bias input bias current ? -0.3 -2 a g vo open loop gain (1) v o = 2v to 4v 65 90 ? db gbw unity gain bandwidth (1) t j = 25c 0.7 1 ? mhz psrr psrr (1) v cc = 12v to 25v 60 70 ? db i sink output sink current v pin2 = 2.7v v pin1 = 1.1v 2 6 ? ma i source output source current v pin2 = 2.3v v pin1 = 5.0v -0.5 -0.8 ? ma v oh output high voltage v pin2 = 2.3v, r1 = 15k? to gnd 5 6 ? v v ol output low voltage v pin2 = 2.7v r1 = 15k? to pin 8 ? 0.8 1.1 v
4 www.fairchildsemi.com ka3842ac/KA3842AE rev. 1.0.1 ka3842ac/KA3842AE smps controller * adjust v cc above the start threshold before setting at 15v notes: 1. these parameters, alt hough 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 = 0 to 0.8v) 4. junction-to-air thermal resistance test environments pcb information: board thickness; 1.6mm, board dimension: 76.2 x 114.3mm 2 , ref.: eia/jsed51-3 and eia/jsed51-7 board structure; using the single layer pcb. output section v ol output low level i sink = 20ma ? 0.1 0.4 v i sink = 200ma ? 1.5 2.2 v v oh output high level i source = 20ma 13 13.5 ? v i source = 200ma 12 13.5 ? v t r rise time (1) t j = 25c, c1 = 1nf ? 40 100 ns t f fall time (1) t j = 25c, c1 = 1nf ? 40 100 ns v olim output voltage swing limit v cc = 27v, c1 = 1nf ? 22 ? v under voltage lockout section v th start threshold 15 16 17 v v tl min. operating voltage (after turn on) 9 10 11 v pwm section d max maximum duty cycle 94 96 100 % d min minimum duty cycle ? ? 0 % total standby current i st start-up current ? 0.2 0.4 ma i cc operating supply current v pin2 = v pin3 = 0v ? 11 17 ma v z v cc zener voltage i cc = 25ma ? 29 ? v electrical characteristics (continued) (v cc = 15v, r t = 10k?, c t = 3.3nf, t a = 0c to +70c, unless otherwise specified) symbol parameter conditions min. typ. max. unit
5 www.fairchildsemi.com ka3842ac/KA3842AE rev. 1.0.1 ka3842ac/KA3842AE smps controller package dimensions 8-pin dip dimensions in millimeters
6 www.fairchildsemi.com ka3842ac/KA3842AE rev. 1.0.1 ka3842ac/KA3842AE smps controller 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. trademarks the following are registered and unregistered trademarks fairchild semiconductor owns or is authorized to use and is not intended to be an exhaustive list of all such trademarks. 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 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, or (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 significant injury to the user. 2. a critical component is 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. product status definitions definition of terms datasheet identification product status definition advance information preliminary no identification needed obsolete this datasheet contains the design specifications for product development. specifications may change in any manner without notice. this datasheet contains preliminary data, and supplementary data will be published at a later date. fairchild semiconductor reserves the right to make changes at any time without notice in order to improve design. this datasheet contains final specifications. fairchild semiconductor reserves the right to make changes at any time without notice in order to improve design. this datasheet contains specifications on a product that has been discontinued by fairchild semiconductor. the datasheet is printed for reference information only. formative or in design first production full production not in production isoplanar littlefet microcoupler microfet micropak microwire msx msxpro ocx ocxpro optologic optoplanar pacman pop power247 poweredge fast fastr fps frfet globaloptoisolator gto hisec i 2 c i-lo implieddisconnect intellimax rev. i18 acex activearray bottomless build it now coolfet crossvolt dome ecospark e 2 cmos ensigna fact fact quiet series powersaver powertrench qfet qs qt optoelectronics quiet series rapidconfigure rapidconnect serdes scalarpump silent switcher smart start spm stealth superfet supersot -3 supersot -6 supersot -8 syncfet tcm tinylogic tinyopto trutranslation uhc ultrafet unifet vcx wire across the board. around the world. the power franchise programmable active droop
|
