Self-Biased Common Drain MOSFET DC Analysis Calculator

Self-Biased Common Drain MOSFET DC Analysis

This calculator computes the DC drain current \(I_{DQ}\) and the drain-to-source voltage \(V_{DS}\) for a self-biased common drain (source follower) MOSFET amplifier.

* Please enter all voltages with their appropriate signs. Set \(V_{DD}=0\) if \(V_{DS}\) (and \(V_{DG}\)) is not required.

Step 1: Enter Biasing Parameters

e.g., 5 V (or 0 if not required)

e.g., 2 V

e.g., 0 V

e.g., 1000 Ω (1 kΩ)

e.g., 5 V (or 0 if not required)

e.g., 0.001 A/V²

Dimensionless (e.g., 10)

e.g., 1 V

MOSFET Saturation Equation (Self-Biased Common Drain): $$ I_D = \frac{1}{2}\, k’\frac{W}{L}\Bigl[(V_G – V_S) – V_{TH}\Bigr]^2 $$

Drain Voltage (when drain is tied to \(V_{DD}\)): $$ V_{DS} = V_{DD} – I_D R_S $$

Drain-to-Gate Voltage (if \(V_{+}\) is provided): $$ V_{DG} = V_{DD} – I_D R_S – V_G $$