Unformatted text preview: s. , 2 , 2 mS
1 , , 10 kΩ b) Find the smallsignal parameters of the BJT transistor ( gm , r0 , rπ ). [3pts]
Since they’re biased identically in each circuit (once again, using the approximation that
1) the BJTs will have identical smallsignal parameters. ,
, , 2.6 kΩ ,
, 1
S
26 , Page 8 10 kΩ c) From a) and b), find the relative magnitudes of smallsignal parameters: [3pts]
i) g m, BJT / g m, MOS
ii) r0, BJT / r0,MOS
iii) rπ , BJT / r0, BJT
, (i) 19.23 ,
, (ii) 1 ,
, (iii) 0.26 , d) Derive the expressions of the output resistances for both cascade amplifiers shown above.
You can drop small terms that are less than 10% of the dominant terms. Using the ratios
you obtained in c), determine which cascode amplifier (CascodeA or CascodeB) has
higher output resistance. [6pts]
1...
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 Spring '07
 KingLiu
 Electrical Engineering, Transistor, voltage gain

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