EE 434 Lcur 22 Bipolar Dvic Modls
Quiz 14 Th collcor currn of a BJT was masurd o b 20mA and h bas currn masurd o b 0.1mA. Wha is h fficincy of injcion of lcrons coming from h mir o h collcor?
1 And h numbr is. 8 6 9 7 5 4 2 3
1 And h numbr is. 8 6 9 7 5 4 2 3
Quiz 14 Th collcor currn of a BJT was masurd o b 20mA and h bas currn masurd o b 0.1mA. Wha is h fficincy of injcion of lcrons coming from h mir o h collcor? Soluion: Efficincy α β B α β 1 α 20mA.1mA 200 α β 1+ β α 200.995 1+ 200
Rviw from Las Tim Bipolar dvic opraion dpndn upon how minoriy carrirs in bas conribu o collcor currn Bipolar modl (in high gain rgion) Diod modl for juncion, injcion fficincy for α B ~ S β ~ S 1 B β Bipolar ransisor is inhrnly a currn amplifir wih xponnial rlaionship bwn collcor currn and This propry maks BJT vry usful β ~ S
Bipolar Modls Simpl dc Modl Small Signal Modl Br Analyical dc Modls Sophisicad Modl for ompur Simulaions Frquncy-Dpndn Small Signal Modl Br Modls for Prdicing Dvic Opraion
Bipolar Modls Simpl dc Modl Small Signal Modl Br Analyical dc Modls Sophisicad Modl for ompur Simulaions Frquncy-Dpndn Small Signal Modl Br Modls for Prdicing Dvic Opraion
Bipolar Modls Simpl dc Modl following convnion, pick and B as dpndn variabls and and E as indpndn variabls
Simpl dc modl From las im : B ~ S β ~ S kt q This has h propris w ar looking for bu h variabls w usd in inroducing hs rlaionships ar no sandard ~ can b shown ha S is proporional o h mir ara A E ~ β 1 S J S A E Dfin and subsiu his ino h abov quaions
Simpl dc modl B ~ S β ~ S kt q B J J kt q S S A β A E E J S is rmd h sauraion currn dnsiy Procss Paramrs : J S,β Dsign Paramrs: A E Environmnal paramrs and physical consans: k,t,q A room mpraur, is around 26m J S vry small around.25fa/u 2
Transfr haracrisics J S.25fA/u 2 A E 400u 2 0.70 0.60 0.50 0.40 0.30 0.20 0.10 0.00 0.1 1 10 (ma) clos o 0.6 for a wo dcad chang in around 1mA
Transfr haracrisics J S.25fA/u 2 A E 400u 2 0.75 0.70 0.65 0.60 0.55 0.50 0.45 0.001 0.01 0.1 1 10 100 1000 (ma) clos o 0.6 for a four dcad chang in around 1mA
Simpl dc modl Oupu haracrisics 300 250 200 d 150 100 50 or B 0 0 1 2 3 4 5 E ds J S A E
Simpl dc modl Br Modl of Oupu haracrisics 300 250 200 d 150 100 50 or B 0 0 1 2 3 4 5 E ds
Simpl dc modl Typical Oupu haracrisics 300 250 200 Sauraion Forward Aciv d 150 or B 100 50 0 0 1 2 3 4 5 ds uoff E Forward Aciv rgion of BJT is analogous o Sauraion rgion of MOSFET Sauraion rgion of BJT is analogous o Triod rgion of MOSFET
Simpl dc modl Typical Oupu haracrisics 300 250 200 d 150 or B 100 50 0 0 1 2 3 4 5 ds E Projcions of hs angnial lins all inrcp h E axis a h sam plac and his is rmd h Early volag, AF (acually AF is inrcp) Typical valus of AF ar in h 100 rang
Simpl dc modl mprovd Modl 300 250 200 d 150 or B 100 50 0 0 1 2 3 4 5 E ds E JS AF B JSA β E 1 + alid only in Forward Aciv Rgion
Simpl dc modl mprovd Modl 300 250 200 d 150 or B E kt q 100 B J A S E + 1 J A 1 S E α F B J SAE J 1 1 SAE α R 50 0 0 1 2 3 4 5 ds E alid in All rgions of opraion AF ffcs can b addd No mahmaically asy o work wih No dpndn variabls changs Trmd Ebrs-Moll modl Rducs o prvious modl in FA rgion
Simpl dc modl Ebrs-Moll modl kt q E B J A S E + 1 J A 1 S E α F B J SAE J 1 1 SAE α R Procss Paramrs: {J S, α F, α R } Dsign Paramrs: {A E } α F is h paramr α discussd arlir α R is rmd h rvrs α α F β F 1-α F α R β R 1-α R Typical valus for procss paramrs: J S ~10-16 A/µ 2 β F ~100, β R ~0.4
Simpl dc modl Ebrs-Moll modl E omplly dominan! B J A S E + 1 J A 1 S E α F B kt J SAE 1 1 JS AE q α R Wih ypical valus for procss paramrs in forward aciv rgion ( ~0.6, B ~-3), wih 26m and if A E 100µ 2 : J S ~10-16 A/µ 2 β F ~100, β R ~0.4 B J SAE J 1 1 SAE α R 10 1.05x10 7.7x10. 28-14 14 10 1 1 10-51 ( ) ( ) Maks no sns o kp anyhing ohr han S E J A in forward aciv
Simpl dc modl Ebrs-Moll modl kt q E B J A S E + 1 J A 1 S E α F B J SAE J 1 1 SAE α R Alrna quivaln xprssions for dpndn variabls {, B } dfind arlir for Ebrs-Moll quaions in rms of indpndn variabls {, E } - 1+β R J A 1 S E β R -E 1 1 J A - B S E β β F R No mor usful han prvious quaion bu in form consisn wih noaion nroducd arlir E
Simpl dc modl Simplifid Muli-Rgion Modl Ebrs-Moll Modl Simplifid Muli-Rgion Modl -E 1+β R E J A 1 1+ S E β R AF 1 1 β β F R E J A - B S E - + E JSAE 1 AF JSAE B β 0.7 E 0.2 Forward Aciv Sauraion B 0 uoff
Simpl dc modl Simplifid Muli-Rgion Modl E JSAE AF JSA B β kt q E 1 + Forward Aciv 0.7 E 0.2 Sauraion B 0 uoff
Simpl dc modl Simplifid Muli-Rgion Modl E JSAE AF JSA B β E 1 + >0.4 B <0 Forward Aciv kt q 0.7 E 0.2 <β B Sauraion B 0 <0 B <0 uoff A small porion of h opraing rgion is missd wih his modl bu sldom opra in h missing rgion
Simpl dc modl Equivaln Simplifid Muli-Rgion Modl β 1 + E B AF JSA B β E >0.4 B <0 Forward Aciv kt q 0.7 E 0.2 <β B Sauraion B 0 <0 B <0 uoff A small porion of h opraing rgion is missd wih his modl bu sldom opra in h missing rgion