EEL3304: Final

NAME:     April 29, 1997

This final exam is open-book, open-notes, and open-calculator. There are three problems.

Make sure you fill in the blanks with your final numerical answers (with proper units!) and make sure that all of your work is shown. You have exactly two hours for this exam. Good luck!

1. (40 points) Answer the following questions assuming that the transistor is biased in the active region ( V) and has a large . Neglect and for the frequency calculations. As usual, and are small ac signals. Use the following component values: , , , , and .
   1. (15 points) Compute the DC operating point.

      Answer summary:
      
      

      
      

      
      

      
      

      
      

      
      

      
      

   2. (10 points) Find the small signal gain / in the midband region.

      
      

   3. (10 points) Find the low frequency pole assuming F.

      
      

   4. (10 points) Find the high frequency pole assuming pF.

      
      

2. (40 points) This problem concerns the crude op amp circuit given below. For each MOS transistor, assume that , and . As usual, , , and are small ac signals. Use the following component values: and
   1. (15 points) Compute the for each MOSFET

      Answer summary:

      
      

      
      

      
      

   2. (10 points) Compute the DC gain

      
      

   3. (10 points) Compute the DC gain . Make sure you get the sign correct.

      
      

   4. (10 points) Compute the output impedance ( ) of the circuit.

      
      

3. (20 points) Short answer
   1. (5 points) Explain why the second transistor stage in the amplifier in problem 2 is needed.

   2. (5 points) Explain the Miller effect and why it is important for the frequency response of the common emitter amplifier.

      Consider the following transfer function:

      

   3. (5 points) Estimate and for this transfer function. (Make sure that your units are correct!)
   4. (5 points) Estimate the midband gain for this transfer function.