Question

Design a double cascode PMOS amplifier that is loaded with a double cascode NMOS current mirror. The current mirror uses an ideal current source with IREF = 200 µA. Find widths and lengths for all transistors, Ron, and Rop given |VOV| = 0.4 V, |VA| = 4 V, Kn ' = 250 µA/V2 , Kp ' = 50 µA/V2 , and AV = −450 V/V.

This is a design problem. Kindly design what you are told. Come up with necessary values that might not be stated above, in order to design it. Thanks.

Answer 1

Let ID be the current in the each half of the amplifier. Assume all MOS to have save overdrive, So

                                                

and

                                                

Assume

                                                                    

The the gain of the amplifier is given by

                                  

Or

                                                  

Or

                                         

Or

                                                         

So

                                                      

So

                                                  

We can choose any value of ID which is multiple of 200uA. So let choose ID = 400uA. Then the PMOS width is given by

                                               

Or

                                   

And