**MOSFET transistor equations**

Here we explain MOSFET transistor equations and we know MOSFET is a multiple junction semiconductor device, multiple parameters make enormous equations based on MOSFET.

So in this post, we include some of the important MOSFET transistor equations.

**N-MOSFET equations **

**Cut-off region **

- Drain current – i
_{D}= 0 - Gate to source voltage = V
_{GS}<_{VTN}

**Linear region **

- Drain current – I
_{d}= K_{n }(W/L). (V_{GS}– V_{TN})V_{DS} - Gate to Source voltage = V
_{GS}> V_{TN} - Gate to drain voltage = V
_{GD}> V_{TN}

**Saturation region**

- Drain current – I
_{d}= ½ K_{n }(W/L). (V_{GS}– V_{TN})^{2} - Gate to source voltage = V
_{GS}> V_{TN} - Gate to drain voltage = V
_{GS}< V_{TN}

**Threshold voltage equation**

** V _{TN} = V_{TO} + ℽ(√2ϕ_{f} + V_{SB} – √2ϕ_{f})**

**Transconductance equation **

** g _{m}=2I_{D}/ V_{GS} – V_{TN}**

**Maximum operating frequency equation **

** f _{T}= g_{m}/ 2π(C_{gs} + C_{gd})**

**P-MOSFET equations**

**Cutoff region **

- Drain current – i
_{D}= 0 - Gate to source voltage = V
_{GS}> V_{TP}

**Linear region **

- Drain current – i
_{D}= K_{p}(W/L) . (V_{GS}– V_{TP}) V_{DS} - Gate to source voltage = V
_{GS}< V_{TN} - Gate to drain voltage = V
_{GD}< V_{TN}

**Saturation region **

- Drain current – i
_{D}= ½ K_{p}(W/L) . (V_{GS}– V_{TP})^{2}. (1+λ . V_{DS}) - Gate to source voltage = V
_{GS}< V_{TP} - Gate to drain voltage = V
_{GD}> V_{TP}

**Threshold voltage equation**

** V _{TP} = V_{TO} + ℽ (√2ϕ_{f} + |V_{SB}| – √2ϕ_{f})**

**Transconductance of equation **

** g _{m}=2I_{D}/ V_{GS} – V_{TP}**

**Maximum operating frequency **

** F _{T} = g_{m}/ 2π(C_{gs} + C_{gd})**