Clif fonstad 1003 lecture 13 slide 3 mosfet

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Unformatted text preview: L) eC ox* Linear iD or Triode Saturation (FAR) iD K [vGS - V T(vBS )]2/2a Cutoff vDS Output family Model valid for vBS 0 and vDS 0, insuring MOSFET iG(vGS, vDS,vBS) 0, iB(vGS, vDS,vBS) 0 Model D + 0 iD vDS for (vGS VT)/a 0 vDS (cutoff) i D(vGS ,vDS,vBS ) (W/L)eCox*(vGS VT)2 /2a iG for 0 (vGS VT)/a vDS (saturation) G + B (W/L)eCox*(vGS VT avDS/2)vDS iB + for 0 vDS (vGS VT)/a (linear) vGS vBS Clif Fonstad, 10/03 S with VT = VFB 2fp-Si + [2eSi qNA(|2fp-Si| vBS)]1/2/Cox* a = 1 + [(eSi qNA/2(|2fp-Si| vBS)]1/2 /Cox (frequently 1) Lecture 13 - Slide 4 BJT Characteristics (npn) iB iC Saturation FAR iB IBS e qV BE /kT vCE > 0.2 V vBE Forward Active Region iC bF iB Cutoff 0.6 V 0.2 V Cutoff vCE Input curve BJT MODELS BJT Models BC vBC Output family CC + + aFiiF aF F ICS ICS iRiR iFF i aaiRiR R R Forward active region: vBE > 0.6 V vCE > 0.2 V (i.e. vBC < 0.4V) CC bFbbFiB i IBS IBS EE Lecture 13 - Slide 5 iR is negligible B+ B+ vCE Other regions Cutoff: vBE < 0.6 V Saturation: vCE < 0.2 V vBE Clif Fonstad, 10/03 IIES ES i iB B B+ B + vBE vvBE BE E E Adding charge stores to the large signal models: A p-n diode: IBS B qAB qAB: Excess carriers on p-side plus excess carriers on p-side plus junction depletion charge. qBC BJT: C iB' bFiB' qBE: Excess carriers in base plus IBS E-B junction depletion charge qBC: C-B junction depletion charge npn (in F.A.R.) B qBE D qG G S E qDB...
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This note was uploaded on 07/20/2009 for the course CSAIL 6.012 taught by Professor Prof.cliftonfonstadjr. during the Fall '03 term at MIT.

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