{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

freq response - ECEN 326 Electronic Circuits Frequency...

Info iconThis preview shows pages 1–11. Sign up to view the full content.

View Full Document Right Arrow Icon
ECEN 326 Electronic Circuits Frequency Response Dr. Aydın ˙ Ilker Kar¸ sılayan Texas A&M University Department of Electrical and Computer Engineering
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
High-Frequency Model High-Frequency Model BJT & MOS C in v 1 f C 1 g m v g mb v 2 E or S 2 r in r x B or G o C or D v r B General BJT MOS r x r b 0 r in r π C in C π C gs C f C μ C gd r o r o r o g m g m g m g mb 0 g mb ECEN 326 Electronic Circuits - Aydın ˙ I. Kar¸ sılayan - Frequency Response 1
Background image of page 2
BJT & MOS Capacitances BJT & MOS Capacitances Active BJT: C π = C b + C je = τ F g m + C je C μ = C μ o 1 - V ψ o n C π C μ MOS: C gs = 2 3 WLC ox C gd : Overlap capacitance C gs C gd ECEN 326 Electronic Circuits - Aydın ˙ I. Kar¸ sılayan - Frequency Response 2
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Transition Frequency, f T Transition Frequency, f T BJT & MOS o C f 1 g m in v 1 r v r x C r o i in i i i o i i i i i o i o i i (s) g m r in 1 + r in (C in + C f )s ECEN 326 Electronic Circuits - Aydın ˙ I. Kar¸ sılayan - Frequency Response 3
Background image of page 4
Transition Frequency, f T Transition Frequency, f T BJT & MOS i o i i (j ω ) g m r in 1 + r in (C in + C f )j ω At high frequencies: i o i i (j ω ) g m (C in + C f )j ω i o i i (j ω ) ω = ω T = 1 g m (C in + C f ) ω T = 1 ω T = g m C in + C f , f T = ω T 2 π BJT: ω T = g m C π + C μ MOS: ω T = g m C gs + C gd ECEN 326 Electronic Circuits - Aydın ˙ I. Kar¸ sılayan - Frequency Response 4
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
BJT-CE & MOS-CS BJT-CE & MOS-CS Small-signal circuit C R S R L V i V o 1 R S R L V i V o g f C in v 1 r in L v o r v m R x o R v r i S ECEN 326 Electronic Circuits - Aydın ˙ I. Kar¸ sılayan - Frequency Response 5
Background image of page 6
BJT-CE & MOS-CS BJT-CE & MOS-CS Transfer function v o v i (s) = K 1 - s C f g m 1 + a 1 s + a 2 s 2 K = - g m R OL R R S + r x = - g m R OL r in R S + r x + r in a 1 = C f R OL + C f R + C in R + g m R OL RC f a 2 = R OL RC f C in R = (R S + r x ) r in R OL = r o R L ECEN 326 Electronic Circuits - Aydın ˙ I. Kar¸ sılayan - Frequency Response 6
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
BJT-CE & MOS-CS BJT-CE & MOS-CS Poles & zeros D(s) = 1 + a 1 s + a 2 s 2 = 1 - s p 1 1 - s p 2 | p 2 | | p 1 | p 1 ≈ - 1 a 1 , p 2 ≈ - a 1 a 2 p 1 = - 1 R C in + C f 1 + g m R OL + R OL R p 2 = - 1 R OL C f + 1 RC in + 1 R OL C in + g m C in N(s) = 1 - s z 1 z 1 = g m C f ECEN 326 Electronic Circuits - Aydın ˙ I. Kar¸ sılayan - Frequency Response 7
Background image of page 8
Miller Approximation Miller Approximation V Z x Z i V o i -A Z i = V i I i = V i V i - V o Z x = V i V i - ( - AV i ) Z x = Z x V i (A + 1)V i = Z x A + 1 Z x = 1 sC Z i = 1 s(A + 1)C = 1 sC , C = (A + 1)C ECEN 326 Electronic Circuits - Aydın ˙ I. Kar¸ sılayan - Frequency Response 8
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Miller Capacitance Miller Capacitance C f in v 1 r in C v o v 1 g m R L r o i v x R S +r Miller Approximation C in v r in 1 o v v 1 g m R L i r o C M v +r x R S C M = (A + 1)C f , A = - v o v 1 = g m (r o R L ) ECEN 326 Electronic Circuits - Aydın ˙ I. Kar¸ sılayan - Frequency Response 9
Background image of page 10
Image of page 11
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}