Electronic – How to find threshold voltage of an NMOS with BSIM3v3 model in LTSPICE

ltspicenmosvoltage

I want to determine the threshold voltage of an NMOS from a bvsim3v3 model in LTSPICE(Not a specific one I'm asking generally for this model). I can't get it directly from the parameters so I want to know how to. It doesn't have to be the exact value, I know it can be changeable but a good approach would be sufficient for me.

One way I thought of is to obtain it from the drain current equation. I set Vgs, W and L myself and measure the drain current with simulation. So this leads to a sub-question: How can I obtain oxide capacitor(Cox) and mobility from the model parameters?

Best Answer

Ground the source, connect the drain to the gate, and feed the drain with a constant current source set to the current value at which you want to know the threshold voltage.

For example:

In Circuitlab this shows a threshold voltage of 4.01V which is actually on the high side of allowable spec.

schematic

simulate this circuit – Schematic created using CircuitLab

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