Re: I have some doubts
Mismatch is a time independent random variation in identically designed elements.
It can occur due to process,electrical parameters.
Gradients between the two identically designed devices can be eliminated by arranging the devices in common centroid or interdigitiged pattern depending on the requirement.
Idea of placing the dummy device is to create same environment there by yielding less mismatch.Let me explain with example U have A(1) B(2) to be matched,we know tht
A B
B A arrangement cacels gradients in both direction.But we have A(1) not two.
A B
B Dummy
Dummy acts like another A device PHYSICALLY but not electrically.
There by satisfying the common centroid rules to have better match.
Capacitors will follow the same rules of matching with others except Random mismatch.
Width of the metal can be selected using DC level of the signal Rather than the AC
>y???Analyze...!!!
Width is decided by current density of tht material.Analyze the Blck's equation for more expertise.
If anything Un answered to the point ,U can bring out for the discusssion
Regards
Mahendra