Lecture 21

# Ming c wu applying millers theorem p in p out 1 rthev

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Unformatted text preview: source overlap/fringing capacitance à༎ CGS –  C2 in parallel with the drain overlap/fringing capacitance à༎ CGD EE105, Fall 2013 Lecture 21 – Slide 10 Prof. Ming C. Wu 5 Example …with MOSFET capacitances explicitly shown CS stage Simplified circuit for high-frequency analysis Lecture 21 – Slide 11 EE105, Fall 2013 Prof. Ming C. Wu Transit Frequency §༊  The “transit” or “cut- oﬀ” frequency, fT, is a measure of the intrinsic speed of a transistor, and is deﬁned as the frequency where the current gain falls to 1. Conceptual set-up to measure fT I out = g mVin I in = Vin Z in !1\$ I out = gm Zin = gm # & =1 I in " jωT Cin % ⇒ ωT = gm Cin 2π fT = EE105, Fall 2013 Lecture 21 – Slide 12 gm CGS Prof. Ming C. Wu 6 Small- Signal Model for CS Stage λ =0 EE105, Fall 2013 Lecture 21 – Slide 13 Prof. Ming C. Wu … Applying Miller’s Theorem ω p ,in = ω p ,out = 1 RThev (Cin + (1 + g m RD )CGD ) 1 ⎛ྎ ⎞ྏ ⎛ྎ 1 ⎞ྏ ⎟ྏ RD ⎜ྎ Cout + ⎜ྎ1 + ⎜ྎ g R ⎟ྏCGD ⎟ྏ ⎟ྏ ⎜ྎ m D ⎠ྏ ⎝ྎ ⎝ྎ ⎠ྏ Note that ωp,out > ωp,in EE105, Fall 2013 Lecture 21 – Slide 14 Prof. Ming C. Wu 7 Direc...
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## This note was uploaded on 01/22/2014 for the course EE 105 taught by Professor King-liu during the Fall '07 term at Berkeley.

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