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Altera_Forum's avatar
Altera_Forum
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14 years ago

can't find the reason Stratix IV GX short-circuited between VCC and GND

hello everyone: i have some questions about Stratix IV GX the first time we configurate the FPGA in jtag, it's display configurate failed at 90%。We check the pcb and find that three pull-...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
14 years ago

Does your board allow to detect easily if it's actually a VCCPT short or a PCB respectively solder short? Also a broken bypass MLCC or tantal cap should be considered.

If the short is actually inside the FPGA, a serious violation of maximum ratings for VCCPT would be the most likely explanation.

By the way, could you clearly detect a short? Core voltage supplies may have low resistance in unpowered state and also show considerable start-up currents in some cases. I'm not sure for Stratix IV, please check the handbook thorougly. It may be also a case of insufficient power delivery of your VCCPT supply.