Lect.6.Intrinsic.Cap

T biasing not shown g m 3 vov c gs 2 l2 in c id e

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: e th e m a g n itu d e o f th e c o m m o n source current gain (|io/ii|) falls to unity ii io • Ig n o r in g e x tr in s ic c a p a c ita n c e , it fo llo w s th a t !T = • (Biasing not shown) g m 3 µVOV = C gs 2 L2 In c id e n ta lly , th is m e tr ic is id e n tic a l to th e fig u r e o f m e r it w e c o n s id e r e d o n th e p r e v io u s s lid e s R. Dutton, B. Murmann EE114/214A 30 A s id e : T r a n s it F r e q u e n c y In t e r p r e t a t io n • T h e tr a n s it fr e q u e n c y is o n ly u s e fu l a s a fig u r e o f m e r it in th e s e n s e th a t it q u a n tifie s g m / Cg s • It d o e s n o t a c c u r a te ly p r e d ic t u p to w h ic h fr e q u e n c y y o u c a n u s e th e d e v ic e – A t h ig h fr e q u e n c ie s , m a n y a s s u m p tio n s in o u r " lu m p e d " tr a n s is to r m o d e l b e c o m e in v a lid – R u le o f th u m b : lu m p e d m o d e l is g o o d u p to a b o u t ω T / 5 • A t h ig h e r fr e q u e n c ie s , d e v ic e m o d e lin g b e c o m e s m o r e c h a lle n g in g a n d m a n y e ffe c ts d e p e n d o n h o w e x a c tly y o u la y o u t a n d c o n n e c t th e d e v ic e – T h e s e e ffe c ts a r e c o v e r e d in m o r e d e ta il in E E 3 1 4 R. Dutton, B. Murmann EE114 31...
View Full Document

This note was uploaded on 02/07/2014 for the course EE 214 taught by Professor Murmann,b during the Fall '04 term at Stanford.

Ask a homework question - tutors are online