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What is Fringe capacitance in Layout

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jagadeesh2k1

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Can any one of u explain what is fringe capacitance in layout?
 

zeeshanzia84

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It the unintentional capacitance that creeps into your design whenever there are two metallic lines in parallel with dielectric in between.
 

jagadeesh2k1

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Can u explain what is Lateral capacitance
 

RDRyan

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You mean finger capacitance in layout?
Finger capacitance is like two combs that fit together.
or your mean parasitical capacitance in layout?
 

jerryzhao

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The capacitor top and bottom plane have some thichness that relate to process technolog. there a capacitor between the top plane's lateral and bottom plane.
detail shown in figure.
 

srieda

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The electric field lines in a parallel plate capacitor are parallel wrt each other. But near the edges of the parallel plates, the charge distribution is non-uniform and hence the field lines are bent.. this effect is called fringe effect...

A similar thing happens between any 2 metal layers in the layout. The places where the plates are planar-parallel, u get uniform electric flux which will lead to coupling capacitances. the regions where the electric lines of force experience fringe, contribute to the fringe effect.
For eg, between a metal1 of 2u width and a metal2 of 1u width running in parallel can cause fringe cap...

hope this helps..
 

jagadeesh2k1

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Is it between different layers or between met1 and met1.
 

analayout

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hi
good explanation by srieda

thanks
regards
analayout
 

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