Does transconductance (Gm) have 3dB bandwidth

Status
Not open for further replies.
M

matrixon

Junior Member level 1
Joined
Dec 1, 2014
Messages
19
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Activity points
151
The voltage gain of an amp is Gm*Zout,
the bandwidth of the voltage gain is limited by the Zout as signal freq increases.
I wonder whether the Gm also has 3dB bandwidth or not.
And If Gm has 3dB bandwidth,what element cause it?
 

Low frequencies have their gain reduced when a coupling capacitor has a higher reactance than the resistance it feeds.
High frequencies have their gain reduced when the output impedance of a transistor is loaded with a capacitance with a reactance that is lower. The capacitance can be the output capacitance of the transistor itself and/or stray capacitance. Therefore gm has a -3dB bandwidth.
 

More than that, the current gain of a BJT as well as the corresponding transconductance gm decrease with rising frequecies due to a decreased mobility of the charged carriers (inertia).
 

Status
Not open for further replies.

Similar threads

Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…