How to size the transistors considering the mismatch?

[didibabawu]

Mismatch sometimes is a important error source of circuits such as differetial amplifier. In order to get better match,we need to use big transistors,but how can i kwon the size i use is big enough but not too big.

3x!

 

[hr_rezaee]

Hi
as I know it depends maximum error that you can neglect in your design and your technology specification.
regards

 

[DenisMark]

Read this paper.
Matching coefficients u can obtain from foundary.

 

[watersky]

sometimes foundry provides mismatch report. perhaps if noise is thought about, the size is bigger.

 

[raduga_in]

Hi didibabawu,

You can also refer for your diffamp design
Raduga

 

[eelinker]

how big is your transistors is a function of how much matching do you need(in terms of variance(sigma) parameters.
there are some formulas relating matching to some technology dependent factors such as AvT and transistors' W*L

 

[lijianheng]

You can refer to Process Design Kit Manual.