How to analyse these circuit?

[wjxcom]

Hi all, please help me to analyse this two circuit:

for a: 1. why the gate of M3 and M4 connect to the drain of MC3?
2. what's the role that R Play?
3. why the gate of MC3 connect to the drain of MC1?

for b: 1. Can this circuit ensure MB5 is in saturation? and why?
2. Can this circuit ensure MC1 and MC2 is in saturation? and why?

 

[holddreams]

You can read RAZAVI's book on page 144,Figure 5.13 ,Figure 5.14,
for low voltage cascode mirrors.

 

[gdhp]

1:For a, the connection is for the bias. and the R is Von/I.
2:The MC1 and MC2 can design in satuation with the input range requiments. and the MB5 is used to bias the MC1,2

The details can be get from the allen or razavi' book!

 

[schwang1970]

It is simple self-bias circuit.