CD-CS Multistage Amplifier CS-CS Multistage Amplifier Q3. One of the techniques to improve the bandwidth of the common-source (CS) amplifier is using a common drain (CD) amplifier before the CS amplifier stage. You want to compare the performance of CD-CS configuration with a CS-CS amplifier configuration in terms of gain and bandwidth. Let all the transistors be identical and at the same biasing current. Let gm = 1.25 mS, RL = 100 KΩ, Cgd = 12π fF a) Find the gain for each circuit. b) Find the poles caused by Cgd shown in each circuit.