MOS_3TDN_Virtual

[Anadig]

I found this spice model is incorrect as I tried to simulate it with MultiSim 11.  MOS_3TDN_Virtual is a depletion mode, n-channel MOSFET and it should be normally on (VTO =0V in spice) unless the VGS is less than 0V.  Please advise it.

Thanks,

Kent

[Tayyab_R]

Hi,

I took a look at the spice model for the virtual mosfet and it seems to have VTO = 0 as you are expecting. Take a look at the attached screen shot.

Hope this helps.

[Anadig]

Yes, the VTO=0 in Spice.  But I was trying to report is when the MOS_3TDN_Virtual got simulated, it doesn't perform the way as a N-Channel depletion mode MOSFET.  If the VTO is set to 0, then device will act as a switch and should stay close all time until the voltage across the gate and source Vgs is less than 0.  But instead, this MOS_3TDN_Virtual acts as an enhance mode MOSFET.  Please run it and let me know whether something I did wrong.

Thanks,

Anadig    

[Tayyab_R]

Hi Anadig,

I looked into this and there is definetely an issue with the depletion mode virtual mosfet. I am filing a CAR(Corrective Action Request) for this issue.

Sorry for any inconvenience.