In a message dated 8/15/2002, Gary McInturff writes:
> Okay, now don't everyone write to my layout guys, but I never bothered to > tell them they could change the constraint files for closer routing on > inner layers, so they do apply the spacings. I have try to keep an eye for > it causing us extra layers or any real grief and it hasn't. > Hi Gary: I agree that for designs that involve only a single telecom port or single power supply, there is often no incentive to take advantage of the tighter spacings allowed on inner layers. For such jobs it is easier for the layout folks if they have one set of simple rules. However, on high density cards with multiple ports, the tighter spacings allowed on inner layers can be a godsend. It is important to keep this in mind when you plan your layout. Also keep in mind that another degree of freedom that was not discussed in this thread is using layer-to-layer separation for the isolation barrier. That invokes another set of complicated considerations, but on some high density boards it can make the difference between "feasible" and "impossible." Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. 781-721-2848 http://www.randolph-telecom.com
