Homework 4
Due: Mon. Feb. 14.
For the following problems, assume K’ = 100 uA/V2, VT = 0.7V, and λ = 0.04V-1 for the NFETS and that the PFETs have the same value only negative.
1. For the following differential amplifier, find Av and rout when ISS = 10 uA and Vin = V1 – V2.

Extra credit: For the above, find the minimum and maximum common mode input voltage (i.e. as if V1 = V2) if all FETs are to remain in saturation.
2. Find Av, rout, and the range of Vout for the source follower discussed in class when VDD = -VSS = 5 V, W/L = 2/1 for M1, M2, and M3, and IBIAS = 50 uA.
3. For the following op-amp, find Av, rout, and the permissible range of Vin and Vout.

4. For the above op-amp, it is determined that the gain is to low and output resistance to high. Name some things you could do to simultaneously correct these problems (i.e. to raise Av and lower rout).
5. For the following op-amp, clearly identify any a) current mirrors, b) current sources or sinks, c) amplifiers (please identify the type of amplifier – differential, inverting, source follower, cascode, etc), and f) any loads (Identify the type of load we are looking at - e.g. active resistor, current mirror, etc. ). Note that a particular FET or set of FETs may fall under multiple categories (e.g. a differential amplifier load may also be a current mirror). VB1, VB2, and VB3 are DC bias voltages. Once you’ve identified the basic components of the op-amp, explain approximately how the device works (just a few sentences).

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Page last modified :February 8, 2005 |