4 ms·
This is all great advice. Making component footprints is the worst. You'd think companies would release footprint files for each part along with the datasheet (
by tomkinstinch 10y ago
This is all great advice. Making component footprints is the worst. You'd think companies would release footprint files for each part along with the datasheet (formatted for different EDA suites), but they don't. Even if manufacturer footprints were available, it would not always be possible to use them, as in the case you point out with making larger custom footprints for QFN parts (a very helpful tip).
For SMT parts, I find 1206 parts to be pretty huge and generally prefer to work with 0805s if I'm hand-stuffing prototypes, but then again I'm a cheap 2-layer masochist, so the extra space over 1206 parts makes a difference. Parts 0603 and smaller are fine for pick and place robots, but for humans they tend to blow away when you sneeze. :)
- bsder 10y agoI'm surprised. The 2-layer masochists I know tend to prefer 1206/1210 parts because they can use the part as a "jumper/extra layer" and sneak a routing trace (or two) in the middle between the two pads. 0805 is okay, but I seem to need a microscope for my eyes. Whereas I can just put 1210 components on a board without any magnification most of the time.
- tomkinstinch 10y agoPassing a trace through the middle is a nice trick, and definitely enabled by 1206s. I'll admit to using that one, particularly for amplifier feedback circuits where one or two parts are 1206s to allow trace pass-through, and the rest being 0805s for density.
- Kliment 10y agoHeh, a 6 mil trace fits easily between the pads of 0603 components. I use that one occasionally.
- arcticbull 10y agoYeah I was about to say the same, you can route an 8 mil trace between an 0805 too IIRC. I'm a 2-layer masochist too, and I tend to use 0603s for most components and 0805s when I want to route under :)
- TaylorAlexander 10y agoStereo zoom microscope off of craigslist was the best purchase I ever made. I got a Leica, but you can get really good Chinese ones for $400. If you do much PCB assembly, they're killer.
- tomkinstinch 10y agoI wish I had a stereo inspection scope... I've seen used boom-mounted dental microscopes on Craigslist or eBay periodically, and can't help but think they would be perfect for PCB assembly. It's amazing how precise our hands can be when we have better magnification. Sub-mm accuracy of movement, which is a weird evolutionary trait if you think about it—more accurate than our unaided vision allows.
- bsder 10y ago> Sub-mm accuracy of movement, which is a weird evolutionary trait if you think about it—more accurate than our unaided vision allows. We access our sub-mm digital accuracy generally by touch feedback rather than by sight feedback.
- zokier 10y ago> Making component footprints is the worst I feel also like the tooling for making footprints is not really that good either. What I'd love to see is full-blown MCAD style drafting system with proper constraints and parametrics etc in a footprint editor. It's bit silly that I have to draw manually the footprints for example different pincount variants for the same standard package instead of making just one base template and driving it with parameters.