2.8. Summary of Key Concepts

Try these first

1. 1.

   What is the condition for an NMOS transistor to conduct?

   Hint

   Think about what the gate voltage needs to do for NMOS.

2. 2.

   When does a PMOS transistor deactivate?

   Hint

   Consider the definition of the threshold voltage for PMOS.

3. 3.

   When does an NMOS transistor turn on?

   • When VGS < Vth
   • When VGS = Vth
   • When VGS > Vth

   Hint

   Remember when NMOS conducts.

4. 4.

   True or False: A PMOS transistor conducts when the gate-source voltage is positive.

   • True
   • False

   Hint

   Consider the opposite of NMOS operation.

5. 5.

   Design a CMOS inverter circuit diagram, label NMOS, PMOS, and show input-output relation. Analyze how it reduces power consumption.

   Hint

   Think about how only one transistor can be active at any time, minimizing current flow.

6. 6.

   Calculate the current through an NMOS in saturation given VGS = 5V, Vth = 1V, Kn = 200uA/V^2, and VDS = 2V with channel-length modulation factor as negligible.

   Hint

   Use the provided saturation current equation to find ID.