EE 140, Spring 1995
Midterm 1
Prof. Boser
Problem #1
In the amplifier shown below the dc bias Idc is adjusted such that all devices operate in the forward active
region.
(a) Find Id2, the drain current in M2.
(b) Find the transresistance Rx = vo/is. Don't neglect the body effect and beware that lambda depends on
channel length.
(c) What are the minimum and maximum output voltages that keep all devices in saturation?
Problem #2
Assume that the all npn reference shown below has a stable operating point without startup problem and that
all devices are in the forward active region. Neglect base currents and device output impedance.
(a) Find Io at 300K.
Hint: find a loop around which all voltages sum to zero.
(b) Find the value of the fractional temperature coefficient(TCF) of Io.
(c) What type of reference is this? (e.g. band-gap, Vt-referenced, etc).
(d) What is the minimum voltage required at the output to keep Q4 forward active?
EE 140, Midterm 1, Spring 1995
EE 140, Spring 1995 Midterm 1 Prof. Boser 1
