niconiconi19h ago
One of the most annoying things in #electronics: you can run a trace under a 0603 resistor, but you can't do that under a 0603 capacitor. The IPC footprints are slightly different, taking the height of the capacitor body into account.
Show threadcpresser18h ago

@niconiconi Works with a 0.25mm trace, but 10mil won't fit.

Revenge of the metric system :)

Slightly related: I was involved in re-generating the RLC footprints a few years ago. We did try to follow IPC as close as possible.

Show threadniconiconi
@cccpresser PCBs are still sold by mils, with a 10 mil/10 mil board being the de-facto cheap class. This is one of the other headaches in electronics: metric feature sizes are always slightly smaller than the imperial feature sizes. If the board design is metric, you're forced to move one step up in the pricing hierarchy, because your metric features exceed the imperial minimal by a few micrometers! In this case, the 0.25 mm trace is under the 10 mil minimum by being 4 micrometers too short!
Jun 15 at 2:58pmWeb
Show threadsconient12h ago
@niconiconi What are the manufacturing tolerances? Would shrinking the cap pad sizes by 2 microns really make a difference?
Show threadniconiconi1h ago
@sconient No, it doesn't. It's a common cheap trick used everywhere. But when you deviate from the standard IPC footprints, part of the blame shifts to you.
Show threadRyan7h ago
@niconiconi @cccpresser had no idea about the diff between mils and metric. I figured if you kept to the manufacturers stated feature size, everything would be ok.
Show threadniconiconi1h ago
@fullywoolly @cccpresser The problem is pricing. The preferred metric and imperial feature sizes are not interchangeable. If they mismatch (e.g. submit a metric-based design to a fab with imperial design rules), you're forced to pay more for stricter tolerance when it's in reality just a rounding error (after converting millimeters to mils, you get 5.9 mil instead of the preferred minimum of 6 mil).