What is the lower limit for Batch PCB SMT components? Geda/PCB is warning me that copper pad placements are too close between the pads of some 0603 (Imperial) chip resistors. What is the recommended lower bound for SMT footprints at Batch PCB?
I’m a Mechanical Engineer by training, a software developer by trade, and this is my first PCB layout. If there’s something obviously wrong with starting out that small (beyond physically placing the parts, that is), then please let me know.
There’s no size limitation other than all pads must be at least 8mils wide and there must be at least 8mils spacing between them. I’ve had to modify a few chip footprints to make the pads smaller to accommodate the 8mil spacing rule. This might be the problem you are having, if the pads are too close together in the footprint.
So, it turns out that this was a metric vs imperial issue. In Geda, there are a few options for choosing between different SMT package types 0603. For example, there is “RESC0603{L,M,N}” and “0603” The former is a metric 0603 resistor, whereas the latter is any imperial 0603 generic part. I used the former and was effectively using imperial 0201.
How should I have known that RESC0603 (or INDC1206) are metric package names, where “0603” is imperial? Is that an EU engineering convention, or is that specifically a Geda convention?