how to calculate drain current in mosfet?

[Harish Achar]

Hai,

Anybody tell me how to calculate n channel mosfet drain current.

 

[hemnath]

look into your datasheet. Manufacturer will specify the drain current.

Best wishes

 

[vvarlord]

ID=Idss(vgs-vt)^2

 

[Harish Achar]

ID=Idss(vgs-vt)^2

what is Idss?

 

[nitishn5]

If you are looking for the drain current in a monolithic MOSFET i.e. an independent NMOSFET/PMOSFET you should look into its data sheet which will give the maximum limits.

If you are in the VLSI scale, you should use the Drain current Equation. For an NMOS

Id = 0.5 µ_n C_ox (W/L) (V_gs - V_th)² (1 + λ V_ds)

If you don't already have the values for the parameters, you might have to do some simulations to find out the values of µ_n C_ox and λ for the technology node that you are using.

 

[rishiraj]

what is Idss?

I(DSS) is the saturation current, the maximum current from drain to source before reaching pinch off voltage (Vp). I(DSS) will be specefied in the datasheet. What nitishn5 said looks perfect to me.