| Thanks to all Earl, Mathew and David for the SMT info. I have one more question. Does anybody have a chart listing the standard, industrial spacings? Perhaps listing in each unit, say XX mils = XX Pitch. Or XX mils = XXmm or something of that nature? Are there standard lead spacings? | Thanks again for all of your help. I'm learning more each day. Someday I'll be an expert on SMT placement, won't my friends be impressed! | -Tim My hat's off to you being only a "salesman." It's refreshing seeing one of you guys going the extra mile to learn technology to better serve customers and, of course, your paycheck - which you will earn on this project. The answer to standard pitch or spacing is but a vapor floating on the breeze. Device suppliers take every opportunity to push the envelop way out of shape. This is both a service and one not so kindly named. As we discussed, the world and everything in it is shrinking. If you want to component type and spacing availability, check JDEC standards and all the suppliers in the known universe. If you want to know what's in the wind, check your barometer. Seriously, the real world knows current "practical" boundaries at the 20 mil pitch level for effective, efficient QFP, as an example, placement. Stretching that, we go to 12 mils and the 0402 chip device world. Stretching that finds us in the yaya land of 0201's. Then we go to BGA and uBGA to gain the space not afforded by using QFP's (you can place them in closer proximity and run multiple traces under them on different layers). uBGA designs are stretching it. I am told by Jason's father that in the Asian technical community, BGA's are not as popular as are flip chip designs. And on it goes - what is impossible today will only be difficult, for a short time, tomorrow. Earl Moon
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