For all hand and spice analysis use the models discussed in class.
 

1. Using the differential amplifier from homework 4 with a load capacitance of 10pF:
1. Calculate the common mode gain and the common mode rejection ratio.  How will the common mode gain change as the common mode input leaves the minimum and maximum voltages calculated on the last homework set?
2. Use spice to plot the voltage output vs. common mode input, and the common mode gain.  On the spice plot draw in a horizontal line representing your hand calculation for common mode gain, as well as vertical lines indicating where you expect the common mode input voltage limits to be.  Explain behaviour outside of those limits.
3. Calculate the pole frequency of your amplifier, and the expected unity gain frequency if you ignore the pole/zero doublet from the current mirror.
4. Calculate the pole and zero frequency of the doublet due to the current mirror.
5. Draw a Bode plot of the differential voltage gain of amplifier with Vcm=0.  (N.B. Bode plot means log gain vs. log frequency, and linear phase vs. log frequency).
6. Use spice to generate the same Bode plot, and annote the plot with your calculations for gain, pole frequency, pole/zero doublet frequencies, unity gain frequency
7. Use SPICE to plot the transient response of the amplifier to a 1mV sine wave input on Vplus with Vminus grounded.  Use three different frequencies: the pole frequency, 5 times the pole frequency, and one fifth of the pole frequency.  Measure the magnitude and phase of the output relative to the input and compare to what you read off of the Bode plot.
8. Plot the transient response of your amplifier to a +/-1mV square wave on Vplus with Vminus grounded.  Again, use the same three frequencies as above.
2. Create a two-stage PMOS input op-amp using your design from homework 4 plus a second gain stage with the same bias current as the tail current of your differential pair.
1. Calculate the differential gain, common mode gain, and common mode rejection ratio.
2. Use spice to plot the common mode gain.
3. Calculate the common mode input range, and the output range of the opamp.
4. Use spice to plot the differential gain at Vcm=-1, 0, and +0.5 Volts, and compare to your hand calculations.
5. Repeat the calculations and plots from Homework 4, problem 5, but now using your two-stage op-amp.