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Altera_Forum
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17 years ago

EP3S150ES VCC/VCCL Resistance to ground

Hi All: We just got a board back, and we are seeing an oddity on the 1.1V supply. We haven't powered the board yet, because of this. Right now we are seeing ~3-4 Ohm resistance to gro...
Altera_Forum's avatar
Altera_Forum
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12 years ago

VCCINT resistance of just a couple of OHMs are normal for larger FPGA's.

To be extra safe, validate your blank board ohms out ok for this supply, then compare to the resistance of a working dev board with a similar part (if you have one)

If you supply is sized correctly it should power up.

For the JTAG issue I was experiencing we had a couple of issues.

One the wrong VCC was connected to the JTAG port, causing reliability issues.

Two the JTAG clock had some transmission line issues, due to the cable assembly required, that was solved by increasing the source termination inside the USB-Blaster from 10 ohm to 33 ohms.

Pete