raja.cedt
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hello mixed_signal, A switch has to be in triode always to give less on resistance. In theory lenght has to be as low as posb to give less Ron, but due to limited supply you have to chose a Lmin based on Vth (typically it varies with L, due to short channel effect it will reduce with length but to reverse short channel effect or retrogate channel profile it may increase with decres in lenght) so simulate and compremise some where. Where as width can be chosen from on state voltage drop, which will be decrease with increase in the width but higher will impact your switch cap settling. So i sugget you to put in siimulation get some set of L and W, now simulate Switchcap.
But one question is you are working with 250nm tech, i guess you will have min of 1.8 supply(up to my knoledge on TSMC tech).
Thanks, Raj.
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