MFETPiMod - Hybrid- Model with Body Eect Let the drain...

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Hybrid- π Model with Body E f ect Let the drain current and each voltage be written as the sum of a dc component and a small- signal ac component as follows: i D = I D + i d (1) v GS = V GS + v gs (2) v BS = V BS + v bs (3) v DS = V DS + v ds (4) If the ac components are su ciently small, we can write i d = ∂I D ∂V GS v gs + ∂I D ∂V BS v bs + ∂I D ∂V DS v ds (5) where the derivatives are evaluated at the dc bias values. Let us de f ne g m = ∂I D ∂V GS = K ( V GS V TH )=2 p KI D (6) g mb = ∂I D ∂V BS = γ KI D φ V BS = χg m (7) χ = γ 2 φ V BS (8) r 0 = · ∂I D ∂V DS ¸
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This note was uploaded on 05/26/2011 for the course ECE 3050 taught by Professor Hollis during the Summer '08 term at Georgia Tech.

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