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AR# 17425

Spartan-II/-IIE - Are the I/O clamp diodes enabled during configuration?


For Spartan-II/-IIE, are the I/O clamp diodes enabled during the configuration process?


No, they are not.

The Spartan-II device is 5V-tolerant during configuration with no external modifications. If the Spartan-IIE device is subject to external 5V signals during reconfiguration, a rise from 3.3V to 5V caused by the disabling of the diodes might occur on the I/Os. You do not need to be concerned as long as the current going into the I/O is limited using a resistor connected in series between the external signal and the Spartan-IIE I/O. Please see (Xilinx Answer 8654) for more information.

For more information on which I/O standards utilize clamp diodes, please see:

(Xilinx Answer 9050)

(Xilinx Answer 10210)

(Xilinx Answer 9048)

AR# 17425
Date Created 09/03/2007
Last Updated 12/15/2012
Status Active
Type General Article