controlling mosfet biasing directly in the circuit question

[yefj]

Hello,I have created a circuit shown below in ltspice using tsmc 180nm mosfets.
unlike the standart way where we bias the mosfets using the large signal furmulas ,I would like to bias the M3,5,1,2 into saturation while M4,6 needs to be linear using charactersitics plots .
How can I make these setting in the circuit below?
Photos and Ltspice files are attached.
Thanks.

https://sites.bu.edu/engcourses/files/2016/08/mosfet-differential-amplifier.pdf

 

[dick_freebird]

M3 cannot be biased into saturation because Vds=Vgs.

The rest will only, at best, be put where you want them at input balance and ideal-ish input & output Vcm.

Classic basic "method-first" design "best practices" are only relevant to some bits of the gain-path at small signal, and steer you wrong when things get real.

Then the real designing starts

Gm/id "methodology", ptui!

"It is like a finger pointing away to the moon"
(befuddled student looks at finger, Plonk!)
"Do not concentrate on the finger or you will miss all the heavenly glory".
- Bruce Lee, "Enter the Dragon"

 

[FvM]

According to usual definition of saturation
VGS > Vth and VDS ≥ (VGS – Vth)
all transistors will be in saturation for useful amplifier operation.