How to increase the drive strength of a Amplifier model

[henry kissinger]

I am using a OP amp model from Keysight ADS.
How parameters I have to change in order to increase the drive strength of this circuit?
The issue I have right now is that the output of the Op Amp is not strong enough as expected due to the capacitance of the Oxide capacitance it connects to.

 

[FvM]

Please show the circuit and the problem you are experiencing with it.

 

[henry kissinger]

Please show the circuit and the problem you are experiencing with it.

Below is the entire circuit, the Op Amp is generating a voltage to Vsink, which then connects to a gate of a NMOSFET.
When the Tox of the NMOSFET is 1e-7, the capacitance is small, so Vsink voltage profile is expected. (-15V->15V)
However for design reason, I need to have the Tox as 1e-9, but then the Op Amp is not strong enough to drive the Vsink because of the bigger oxide capacitance at the NMOSFET.
How should I modify the Op Amp (changing the parameters) to give expected Vsink at Tox=1e-9

 

[FvM]

The fictive "OP Amp" with 10 GHZ bandwidth and infinite slew rate is effectively working as square wave voltage source, limiting parameter is the large Rout of 100 ohm. Don't know which real components you want to model with the circuit. If you are looking for a real component, use a fast gate driver. As ideal driver, you can simply place a controlled voltage source, but with lower output resistance.

 

[dick_freebird]

Vcvs and whatever R you like, appended?

For more of a simple current boost, a v=0 series source between amp and load, and a paralleled ccvs with (say) a=9 would give you a straight 20X drive increase without touching the guts.

 

[BradtheRad]

You set op amp for 100 ohms output impedance. That's greater than an old-fashioned 741, looking at its internals (below). Notice resistor values of 25 & 50 ohms at its output stage. This means with a load of 500 ohms, voltage at load is dropped 5 to 10 percent automatically.

Similarly your 100 ohms has the effect of limiting current. Try a lesser value such as 10 ohms.

 

[dick_freebird]

Vcvs and whatever R you like, appended?

For more of a simple current boost, a v=0 series source between amp and load, and a paralleled ccvs with (say) a=9 would give you a straight 20X drive increase without touching the guts.

That should have been cccs... thanks, Chrome spell-guesser.