MOS Transistor Sizing (analog, digital, and mixed)

[jimjim2k]

analog transistor sizing

Hi


I have always wondered about the handy rules for transistor sizing in analog, digital and mixed signal ciruits.

Would you please share your experinces or yor handy rules for
MOS transistor sizing,


tnx

 

[dwang_w]

transistor sizes 2004

digital circuit can use the minmux rule; analog must use large size according to need such as current circuit;

 

[guamak_menanak]

mos transistor sizing

we used bigger size of gate to ensure circuit realibility...

 

[sutapanaki]

Make a plot of Id vs. Vdssat for different W/L a parameter. This will give you an idea what sizes to chose for given current, overdrive and gm.

 

[fun.zhao]

Digital: channel length is the minimum process length
Analog: W/L & length changed with specification and experience

 

[cascode]

My prefered method is to use the 'level of inversion' method that has emergerd from the EKV model.

Advantages:

1. Current based - most analog circuits are biased with current sources.
2. Good for all operating area of the MOSFET (weak, moderate and strong invertion)
3. The continuous equations from the EKV model can be used to calculate gm, noise...

There have been several papers/presentations on the subject.

 

[isaacnewton]

See the following post: