n"A A B A A AAA AA AAAAAA B A B B B BAA A VREFVCCOUTPUTGROUNDRT/CTISENSEVFBCOMP'%C:\psimwork\PWM-IC\Uc3842\Uc3842.SCH DDQw?V.TIMEIך>{Gz?GroundR DIODESSWIVPVDC#P&COMP0ORGATE1NOTGATE4SRFFEVSENGONCTRLJCTOPQVVCVSSIVCCS`IDCpZENER OP_AMP_2]pCCC4CzCC??p#D hZ313A@{!AZC7ChCS!CV}aC~C??34 Courier Newqrqr@@r@13y!cCWCC|CxC7C?? Oscillator Courier NewB@Bt"S?D DSHD~DCDٱD??Logic Courier NewA@Av:[*Dg-C6DiC[CCCC??10 Courier Newqrqr@@r@i_kCCCCCC??%D hVDC40@{C>C&2CC\CC??16 Courier Newqrqr@@r@k\CHCCpCC\C??4"D hSRFF1PNBCCCCCC??ppABCzCCCCC??@BC>CCCCaC?? B BC>CC>CC>C??ppABCHCCHCCHC?? ABCHCCRCCMC??@BCpCCpCCpC?? ABCfCCpCCkC??@BCRCC\CCWC??@BC\CCfCCaC??@OCCCCCC??D hGroundgC%DC*DC'D?? -D hD1`-kC%DC*DC'D??1D hR1R@`-|gQCG!DC1c%DCD%Df6=D?? Comparator Courier NewB@BxX;D8Dd)LDCC*CB??4C\C>CpC*CfC?? 4^D>ChDRCcDHC?4CC>CC*CC??4C@D>CED*CCD??4^DDhD DcDD?? B\DD^DD@]DD??@MRDD\D DWDD??1D hNOT2BODDRDDPDD??@ND"DD*DD@&D??D hIcomp  CcDC$hD͈CBeD??J or N Package; D8 Package Courier NewjRÑjRCAjRCv CkDn,SCoD74CBRmD??1: COMP Courier New‘BABu CpD8oJCtD70CBRrD??2: VFB Courier NewAAAxCuD֦dCyDkS=CBRwD?? 3: ISENSE Courier New9‘9BA9BwCzD[C~D8CBR|D?? 4: RT/CT Courier NewQ%‘Q%BAQ%BxCzDjSC~DCBR|D?? 5: GROUND Courier New9‘9BA9BxCuDjSCyDCBRwD?? 6: OUTPUT Courier New9‘9BA9B C^Dr޸C$cD9oCB`D??DIL-8, SOIC-8 (TOP VIEW) Courier New‘BABuCpD7CtDCBRrD??7: VCC Courier NewAAAvCkD6CoDKCBRmD??8: VREF Courier New‘BAB4C'D>C,D*C*D??4C4D>C9D*C6D??B6CfCCfCCfC??@a=DBD C D C?S'D hIVCCS2A"0I +?|B@D}C=D?CDj= C??11m Courier Newԕ-ԕ-A@-A=A"0B@ D C D*C D%C??@OADBD CDC??D hGroundB\ DB DC DB??@giCCCCCC?? -D hD2`-kpCDC"DzC@D??1D hR8R@`-kpC DCDzCD??1D hR7R@`-]CCCCCC??##D hP1A"0K=U?]CCCCCC??##D hP2A"0n?`CHCCpCC\C??E&D hVSEN1A"0?8RC4CzCHCfC>C??GNDBzCBzCCzCB??@BCBCRCC%C??4B4BzCBCBCB??ppABC\CC\CC\C??A`'DRC4DzC-DfCE&D hVSEN2A"0?BzCCCCCC??ppABzCCCCCC??ppA`CCCCCC??E&D hVSEN3A"0?BCCCCCC?? ABCCCCCC?? ABCCCCCC??@BCCCCCC?? BBCCCCCC??@BCCCCCC?? BBCCCCCC??ppABCCCCCC?? BBzCCzCCzCC?? ABzCCzCCzCC??@BCCCCCC??@BCCCCCC??@BCCCCCC??ABzCDCDCD??ppABCDC%DCD??ABCCCCCC??AB %DC%DD%DC??B8RC DzC%DfC"D??GND9RCDzC DfC D??VREF9D>C DRCDHC?VREF8CCCCCC??GNDB DC DC DC?? BB DC DD D D??BBCC DCCC??B8#RCCzCDfCC??GNDB'zCCCCCC??A`( D%DD/D@D*D??E&D hVSEN4A"0?8)CED DJDDHD??GNDB.'D,D'D6D'D1D??AB0'D6D/D6D@+D6D??ppA`1 D@DDJDDED??E&D hVSEN5A"0?84 D1DD6DD4D??GNDB5 D,D D4D D@0D??ppAB8DEDDEDDED?? AB9D/DDEDD@:D??4B4B:zC>CzCfCzCRC??AB;zCfCCfCCfC??ppAB=zC4CzC>CzC9C??@8> D CD4CD*C??GND8? DCDCDC??GNDBID*DD*DD*D??@BJD'D D'D@D'D??ppABLD4D D4D@D4D??ppABNC'DC'DC'D??ppABO;D6DCD6D@?D6D??ppABR>CBzCB\CB??ABT>CfCzCfC\CfC??ABV>CCzCC\CC??ABX>C*DC*DkC*D??44BBZ>C6DC6DC6D??BB\>CCD DCDCCD??44CB] DD/DDDD??BB`/DD/D1D/D'D?? BLaCDDOD"D@IDD??0D hOR2tbC"DC,DC'D??:D hOP_AMP2P@PgC DXlCo$DĠC"D??OP_AMP2 Courier New""A@ AbD hBdC'DC6DC/D??ABeC,DC4DC@0D??ppAahD\C"DCDpC??Q'D hVVCVS1A"0@zR%#D7blC6$D{C $D "tC??5 Courier Newqrgqrg@@rg@hA"0NkC\CDpCDfC??JD hCTOP4BnDzCDCDC??@BoDC DCDC?? AB~DC DCDC??AB D4C DHC D>C?? AB'DHC'D\C'DRC?? AB DC DC DC?? AB DC'DC#DC??ppAB'DpC'DC'DC??AB DHC D\C DRC?? AB4DfC4DC4DC??B9DAZBPDYB+DٵB??*11 mA is the IC operating supply current. Courier NewPEÝPEC@PECtCQDDUDU7D~SD??Note: Courier NewA@Av D MSDRrD -WDdd>D=UD??;- All functions of the IC are modelled, including the UVLO Courier NewQÝQC@QCd DsfDoD]djD=DhthD??9- This model applies to UC1842 (Ta = -55 oC to +125 oC), Courier New"JÝ"JC@ JCP DNpDD8tDYDCrD??Y- After modifying the UVLO threshold, the model can also be used for UC1843/2843/3843. Courier NewÝC@CDWD- UCx842 and UCx843 can operate the duty cycle close to 100%; Courier New\Ý\C@\CK DDKg}DDYEDD???whereas the maximum duty cycle for UCx844 and UCX845 is 50%. Courier New6`Ý6`C@6`CBC4DC4DC4D??BBCC%DCDC??C D DY0DDGDD??F- A grounded op. amp. (OP_AMP) can be used for the error amplifier Courier NewayÝayC@byC'i D)DDDID$D??Eif the IC reference ground is connected to the power circuit ground. Courier NewuÝuC@uCC A2!D\JB;Dd!B??PSIM Model for UC3842 Courier New'þQ%'CQ%A'CBCB DBCB?? CB'DHC^DHCCDHC??BB DHC'DHC#DHC??ppAB DB DBDB?? BBDCDfCD>C?? BBDfCDfCDfC?? BB%DC4DC,DC??AbD\D?D`DpDD^D??B- The propagation delay is not modelled. It can be included by Courier New:kÝ:kC@8kCD~R`DuDh2dDBDsBbD??:adding time delay blocks (TDELAY) at the gating output. Courier New!NÝ!NC@!NC .END