HI
I have a Xilinx Spartan3e IO pin connected to a system bus signal. The system bus signal can be active (3.3v/0v) even when the Spartan device is powered off. When the signal is at 3.3, I suspect the ESD protection diode between pad and VCCO on the Spartan IOB is going to turn on. Does anybody know what would be the current drawn?
-Dipankar
Get a multimeter and measure the current! I would also observe the Vcco (I/O supply voltage) while the pin is being driven High. Most devices have a strong diode between any I/O pin and its Vcco supply pin. Some devices claim to be "hot pluggable" and avoid this diode-clamping somehow.
Peter Alfke, Xilinx Applications
~ 2 mA per bank.
Austin
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