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)