Frequency Response of CG, CB, SF and EF

 Page 1


Frequency Response of
CG, CB,SF and EF
Page 2


Frequency Response of
CG, CB,SF and EF
Common Gate Amplifier
Substrate is not connected to 
the sourced must account 
for body effect
Drain signal current becomes
iD ( S m V gs § mb ^ bs )
And since vg l = v ,„
Body effect is fully accounted 
for by using s m -> (gm + gm b )
000
Page 3


Frequency Response of
CG, CB,SF and EF
Common Gate Amplifier
Substrate is not connected to 
the sourced must account 
for body effect
Drain signal current becomes
iD ( S m V gs § mb ^ bs )
And since vg l = v ,„
Body effect is fully accounted 
for by using s m -> (gm + gm b )
000
Common Gate Amplifier
V
Page 4


Frequency Response of
CG, CB,SF and EF
Common Gate Amplifier
Substrate is not connected to 
the sourced must account 
for body effect
Drain signal current becomes
iD ( S m V gs § mb ^ bs )
And since vg l = v ,„
Body effect is fully accounted 
for by using s m -> (gm + gm b )
000
Common Gate Amplifier
V
1 C - Common Gate Amplifier
Page 5


Frequency Response of
CG, CB,SF and EF
Common Gate Amplifier
Substrate is not connected to 
the sourced must account 
for body effect
Drain signal current becomes
iD ( S m V gs § mb ^ bs )
And since vg l = v ,„
Body effect is fully accounted 
for by using s m -> (gm + gm b )
000
Common Gate Amplifier
V
1 C - Common Gate Amplifier 1 C - Common Gate Amplifier
S m § mb
where Aa £ (gm + gm b ) r „
Taking rQ into account adds a component (RL /A0 ) 
to the input resistance.
The open-circuit voltage gain is:
The voltage gain of the loaded CG amplifier is:
R
L
R, +r + A R
L o vo s