Quote from: Ostenbacken on January 18, 2014, 04:20:29 PM

Quote from: Lucko on January 18, 2014, 02:57:57 PM

So 95A... It is tested and it works(on a different board)... So don't worry...

Ok, at least it sort of works. I already ordered the PCBs so I'll probably just run the modules overloaded or reduce the hash rate. But it's a bad engineering practice. Do you think TI's engineers were not tempted to quote higher values in their datasheet if the device was really capable of providing more output current? These days everything is around marketing, and part manufacturers sometimes quote very optimistic values that are only achievable in very controlled circumstances, while in real applications the part can't be realistically expected to deliver that performance. So there must be reasons why their nominal output current is limited to 50A, not more.

Overcurrent protection is just a safeguard against unexpected, exceptional overloads but not a guideline to constantly run your device at currents between 50 and 95A. If you constantly violate datasheet requirements in your designs, you're simply asking for trouble. Say, if this module fails catastrophically, not only it will cost you some $40-$50 to replace it, but it could also fry 16 of your Avalon chips. In the end you may lose a whole board with all parts.

I would consider reducing the number of chips on the board to 12-14 or making a custom VDD voltage regulator in place of the PTH12040 module. The latter approach could also save costs considerably. I have some experience with switching mode power converters, but not at these high currents.

I share your cause for concern here. My uncles worked at TI 30 years as a lead engineer I'll run it by him. I have several years of experience myself. 2 years in Metrology constantly having to bring engineers back to the real world, because measurements are only as reliable as the instrument taking the measurement, and of course they would quote higher values if there was any chance it was capable.

They show on the graphs optimum current output is 35A, 50A is the absolute maximum. The derating curve suggests component breakdown over 50A. I didn't have a chance to examine the justification for your estimates. Is there any chance that they're off?