I think I fried my I/O bank... (virtex-E question)

Quick question... I've been using a Virtex-E fpga on a development board that provides jumpers to connect or disconnect Vcco for each I/O bank. Some of my inputs are LVDS, and one of my signal sources has LVDS output that swings up as high as ~2.4V at the highest. On one of my last test runs I accidentally left the Vcco jumper uninstalled for the IO bank that this device was connected to, meaning that Vcco for that bank was left floating. To make a long story short, much current was drawn, and now (probing the FPGA pins directly) Vcco for that I/O bank appears to be shorted to ground inside the chip package(~1.5 ohms from Vcco pin to Gnd pin).

To anyone out there who's familiar with Xilinx hardware, would the mistake I made above (no Vcco for a ~2.4V input LVDS signal) have caused the IO bank to become damaged? I'd just like some confirmation that this is the cause, before I power up the FPGA board and fry another IO bank...

Reply to
NotTooSmart
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Not,

Seems extremely unlikely. It is true that without Vcco connected to anything, the ESD protection as well as the other protection circuits for large positive voltages is not well protected.

Is this attached to a long cable? If so, you may blow out the IOBs even with the Vcco connected (inductive kickback can cause very large voltages).

For long cable applciations, clamp diodes are almost required.

Aust> Quick question... I've been using a Virtex-E fpga on a development

Reply to
Austin Lesea

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