1. What is N-Channel MOSFET Current?

The drain current (I_d) in an N-channel MOSFET is the current that flows from the drain to the source when a voltage is applied to the gate. This calculator computes the current in the saturation region using the square-law model.

2. How Does the Calculator Work?

The calculator uses the N-channel MOSFET current equation:

Where:

• \( I_d \) — Drain current (A)
• \( \mu \) — Carrier mobility (m²/V·s)
• \( C_{ox} \) — Oxide capacitance per unit area (F/m²)
• \( W \) — Channel width (m)
• \( L \) — Channel length (m)
• \( V_{gs} \) — Gate-source voltage (V)
• \( V_{th} \) — Threshold voltage (V)

Explanation: The equation models the saturation region current where V_gs > V_th and V_ds > (V_gs - V_th).

3. Importance of Drain Current Calculation

Details: Calculating drain current is essential for designing MOSFET circuits, determining power consumption, and analyzing circuit performance in amplifiers, switches, and digital logic circuits.

4. Using the Calculator

Tips: Enter all parameters in the specified units. Ensure V_gs > V_th for meaningful results. Typical values: μ = 0.03-0.07 m²/V·s (electrons), C_ox ≈ 3.45×10^-3 F/m² for 10nm oxide.

5. Frequently Asked Questions (FAQ)

Q1: What is the saturation region?
A: The region where drain current becomes nearly constant despite increases in drain-source voltage (V_ds).

Q2: What if V_gs < V_th?
A: The MOSFET is in cutoff region and I_d ≈ 0.

Q3: What are typical mobility values?
A: For silicon MOSFETs: ~0.05 m²/V·s for electrons, ~0.02 m²/V·s for holes.

Q4: Does this work for P-channel MOSFETs?
A: No, this is specifically for N-channel. P-channel has different characteristics.

Q5: What are limitations of this model?
A: It doesn't account for short-channel effects, velocity saturation, or subthreshold conduction.