Pulsed Sources in Keysight ADS

[HariHerekar]

Hey all,

I plan to simulate the effect of pulsed Drain-Source voltage on a GANFET model. Basically i would like to apply a simple DC Pulse train to the Drain-Source terminal and measure the ID and VDS.
The problem is that ADS treats sources like VtPulse as a short circuit during DC simulations. I dont want to perform a transient simulation, rather a DC one by sweeping VDS and plotting against ID.
Any ideas how I can achieve this ?

 

[FvM]

VtPulse is a time domain (transient simulation) source. Behaviour in other simulation modes can be set by additional simulation sources in series with VtPulse.

 

[dick_freebird]

Pulse source has DC, tran initial and pulse levels in all the SPICEs I've used. It would seem peculiar to not have legacy source params.

For initial conditions to be useful the DC and initial values should be the same.

 

[FvM]

ADS isn't SPICE. VtPulse source has definitely no DC or AC parameters.

 

[HariHerekar]

I would like to use the Pulsed DC source (Vtpulse), to do a DC simulation. But in the DC simulator, time dependent sources such as Vt pulse are treated as short circuits.
Any idea how i could combine sources so that i can do a DC sim with a Pulsed DC source ?

 

[FvM]

There are no time variant signals in DC analysis. Please explain what you want to achieve. What shall be the purpose of pulsed source?

 

[HariHerekar]

Hi, its simple actually. A B1500a curve tracer by keysight allows you to perform simple DC Characterization (IDSvs VDS) using a pulsed input voltage. The purpose being to prevent excess heating of the junction. Eg: VDS is held at 5 V for 200usec, ID measured, and a period of 1msec is given for the MOS to cool down, after which more measurements are done. This effectviely looks like we sent a pulsed DC voltage across VDS.

My efforts are the recreate this testing environment on ADS. DC simulation allows me to sweep VDS and plot ID but the VDS held is constant, and my transistors thermal circuit treats it as such. I would love to use a pulsed source across VDS, plot the corresponding IDS, and move onto another point. But the problem I face is that transient simulations such as these take too long and consume too much of my resources.

I have moved on from ADS now, thank you for your help.

 

[BigBoss]

During DC Simulation, ALL Transient/HB Sources are treated as Short Circuited in according to theory.

 

[FvM]

If you want to plot transistor characteristic curves in simulation, you don't need pulsed sources because usual transistor models don't simulate thermal behaviour. If they do, you can simply "short" junction temperature to a fixed value.
If you however want to simulate a pulsed transistor tester, there's no other way than using transient mode. Hard to believe that simulation of a single transistor takes too much time.