May 1, 2000, Questions 1-4 have been marked. More Comments Shortly.

Exam Comments

Question 1. Bias currents wll answered. Cascode transistor setting a voltage wasn't known by about a third of the students. Some trouble with negative input common-mode range. Many assumed that it has the same Von as other transistors. It didn't.
Question 2. Generally well answered, but not all knew what frequency to use.
Question 3. So far the best answers for this one. Mainly numerical slips.
Question 4. Resistor equivalent had two positive resistors, one negative resistor. Some did not specify the negative resistor. Most people wrote charge balance equation for one phase only, even though the question said charge flows on both phases. Also, on a particular phase, if a capacitor is disconnected from the circuit, it does not participate in charge balance. Many people included all four capacitors in their equations whether or not they were connected. This was probably because they were trying to use one equation only to solve the problem.
Question 5. Noise.
Question 6. Short Answers.