regarding non default rule

[venkatramanan]

what is the main purpose of using non default rule?already we having rules in tech lib?then y we are using that rule is clock specification file?

 

[yadavvlsi]

We normally define double width double spacing (DWDS) rule for clock nets. It can be double width triple spacing also. Clock network is always switching network and draws a lot of current. Double width for clock nets is used to avoid electromigration and double spacing to avoid crosstalk issues.
Electromigration - Wikipedia, the free encyclopedia
Crosstalk (electronics) - Wikipedia, the free encyclopedia

 

[venkatramanan]

thank u another one doubt ...what is the differnce between clk buffer and normal buffer?
i know that clk buffer having equal rise time and fall time.and normal buffer not like that.but they asking what is schematic diagram for both what is funtional operation for both?

 

[pavanks]

The Clock buffers would be bigger than the normal buffers in size.
U need equal rise and fall times for clock so that u have same amount of duty cycle.

Hope it helped....

 

[jeevan.life]

Schematic will be same except for extra LVT or HVT layers. Functional operation ish. also the same except that clock buffers are used in clock paths and normal ones in data pat