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John Larkin Highland Technology, Inc picosecond timing precision measurement
jlarkin att highlandtechnology dott com
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- posted
4 years ago
mixed FR4 and microwave dielectrics
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- posted
4 years ago
Back in 1988, we specified isocyanate resin bonded teflon (PTFE) cloth as t he outside layers of our six-layer delay board, so we could route the 800MH z clocks and the sub-nanosecnd logic transistions around without losing too much edge speed. The inner layers were all FR4 epoxy resin bonded glass fi bre.
It was a triple extended Eurocard (big), but came out flat.
What did you do wrong?
-- Bill Sloman, Sydney
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4 years ago
John Larkin wrote in news: snipped-for-privacy@4ax.com:
So, the other type of MEMS....
Macro Electro-mechanical systems.
Needs a more stable spin.
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4 years ago
IIRC, the fab told them it was a bad idea, customer said go ahead and make it, and evidently the fab believes the customer is always right.
You ALWAYS make the board stack symmetrical. Whatever you're doing on one side, you're doing on the other side. Same cores, same prepreg, same copper thickness, same copper density. Otherwise you get something like this. :-)
Tim
-- Seven Transistor Labs, LLC Electrical Engineering Consultation and Design Website: https://www.seventransistorlabs.com/
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4 years ago
Except for cost, what is wrong with using mixed PPO (Panasonic, Isola)