5.4. Small Signal Model of MOSFET

Try these first

1. 1.

   What does the small signal model represent?

   Hint

   Think about linear approximations.

2. 2.

   Define transconductance in relation to MOSFETs.

   Hint

   Consider its role in proportional changes.

3. 3.

   What is the small signal model of a MOSFET represented as?

   • A current-controlled voltage source
   • A voltage-controlled current source
   • A resistor

   Hint

   Think about how the MOSFET operates.

4. 4.

   Transconductance (gm) refers to the ratio of which quantities?

   • Output voltage to input voltage
   • Change in output current to change in input voltage
   • Input voltage to output current

   Hint

   Consider the formula for gm.

5. 5.

   A MOSFET has a threshold voltage (Vth) of 0.7 V, and operates with ID of 10 mA at VGS = 3 V. Calculate its transconductance and its output current for a small signal VGS = 0.01 V.

   Hint

   Use the transconductance formula and plug in the values carefully.

6. 6.

   Explain how the small signal model assists in determining the bandwidth of a MOSFET amplifier, given you're varying Vgs to analyze performance.

   Hint

   Focus on gain response in relation to frequency adjustments.