To find the W/L ratio of the n-channel MOSFET, we use the standard equation for the drain current in the saturation region of a MOSFET:

$I_D = \frac{k'_n}{2} \cdot \frac{W}{L} \cdot (V_{GS} - V_T)^2$

Where:

• $I_D$ is the drain current,
• $k'_n$ (or $\mu C_{ox}$) is the process transconductance parameter,
• $V_{GS}$ is the gate-to-source voltage,
• $V_T$ is the threshold voltage,
• $W/L$ is the width-to-length ratio of the MOSFET.

Given values:

• $I_D = 1 \, \text{mA}$,
• $k'_n = 0.6 \, \text{mA/V}^2$,
• $V_{GS} = 1.4 \, \text{V}$,
• $V_T = 0.8 \, \text{V}$.

Step 1: Plug in the values into the equation

$1 \, \text{mA} = \frac{0.6 \, \text{mA/V}^2}{2} \cdot \frac{W}{L} \cdot (1.4 \, \text{V} - 0.8 \, \text{V})^2$ $1 \, \text{mA} = \frac{0.6}{2} \cdot \frac{W}{L} \cdot (0.6)^2$

Step 2: Simplify

$1 \, \text{mA} = 0.3 \cdot \frac{W}{L} \cdot 0.36$ $1 \, \text{mA} = 0.108 \cdot \frac{W}{L}$

Step 3: Solve for $\frac{W}{L}$

$\frac{W}{L} = \frac{1 \, \text{mA}}{0.108} \approx 9.26$

Thus, the W/L ratio of the MOSFET is approximately 9.26.

Do you want further details or have any questions?

Here are 5 related questions to expand this topic:

1. What happens to the MOSFET current if the W/L ratio is increased?
2. How does $V_{GS}$ affect the operating region of the MOSFET?
3. What are the differences between linear and saturation regions in MOSFET operation?
4. How does changing $k'_n$ (process parameter) impact the MOSFET's performance?
5. How can one adjust the threshold voltage $V_T$ in MOSFET design?

Tip: In MOSFET design, increasing the W/L ratio improves the drive strength, allowing for higher current at the same gate voltage.