MOSFET capacitor

[[email protected]]

Hello,
I am designing an IC amplifier and i want to remove the DC component
from the output.
I thought of using a capacitor.
How can i implement a capacitor using a MOSFET. I heard i can connect
the drain to source but how do i control the equivalent capacitance?

 

[Pooh Bear]

Hello,
I am designing an IC amplifier and i want to remove the DC component
from the output.
I thought of using a capacitor.
How can i implement a capacitor using a MOSFET. I heard i can connect
the drain to source but how do i control the equivalent capacitance?

Maybe you could elaborate on the exact meaning of " I am designing an IC
amplifier " first before going any further ?

Graham

 

[Jim Thompson]

Hello,
I am designing an IC amplifier and i want to remove the DC component
from the output.
I thought of using a capacitor.
How can i implement a capacitor using a MOSFET. I heard i can connect
the drain to source but how do i control the equivalent capacitance?

MOSFET capacitance is simply the gate capacitance.

HOWEVER: There is a series resistance component which varies with
bias, and it is NOT modeled by the MOSFET Spice model alone.

...Jim Thompson

 

[josh lawton]

I think you need to spend some more time learning the process. You may
have a capcitor option wich gives less voltage dependence by using a
high implant, or possibly poly-poly capacitor.

Be careful when using a normal pmos or nmos as a capcitor. If you are
below the threshold volatge the capacitance is very low. Using a
depletion device can solve this.

 

[Clark]

If you need to ask this, it would be best to forget it.