Posted Jan 28, 2011, by Patrick Carrier
Many designers go to great lengths to make sure they do appropriate length-matching, even to the level of including the lengths of their terminators (resistors) in their routing. Although this seems like a way to be ultra-precise, it is actually being less precise. The reason is that the body length of a resistor is very small compared to the change in edge rate and thus real delay caused by the resistor.
For … Read More
Tags:
Constraints,
HyperLynx,
timing,
length match
Posted Jan 27, 2011, by Patrick Carrier
Yeah, that’s what I said. Vias are longer than their length. Phrased more appropriately, the delay introduced by a via has a lot more to it than just the length of the via. For starters, signals propagate through vias much differently than they propagate through traces. So trying to length match and include “via lengths” doesn’t make much sense in your layout. If you really … Read More
Tags:
Constraints,
HyperLynx,
vias,
timing
Posted Jan 25, 2011, by Patrick Carrier
Too often I see people just using straight length to manage their board timing. Or take it one step further and turn length into propagation delay.You know, 1 inch is about 166ps. Which is true, but nowhere near the complete picture for timing. If you think about it, the whole reason we have length constraints is to make sure data arrives at a certain time. That means that the signal switches above … Read More
Tags:
Constraints,
HyperLynx,
timing,
length matching
Posted Feb 24, 2010, by Steve McKinney
I’ve been on a bit of a blogging hiatus, but hopefully I’m returning to a more regularly scheduled program. Consider it like the Olympics that has interrupted your regular TV programming for the last 2 weeks to show you people who have committed their lives to their passion. I enjoy it - some of those people do amazing feats often risking life and limb to be the best in the world at what they do.
The … Read More
Tags:
HyperLynx,
Olympic,
Constraints,
Pre-Layout
Posted Oct 30, 2009, by Steve McKinney
Around the Western world tomorrow, kids of all ages (include some of us adults) will be celebrating Halloween. For those of you that may not know what Halloween is, it’s a celebration that originated from an old Celtic tradition where fires were lit to ward off evil spirits on Samhain - Summer’s end. This was a special night because the people of the time believe that during this night, the separation … Read More
Tags:
Halloween,
HyperLynx,
Constraints,
Pre-route,
LineSim,
Planning
