I/O pin impedance

Spartan-3 USB 2.0 Modules
1

Hello,

I was wondering if any of you knew the I/O pin impedance on the XEM3001? also I know the voltage on the pins are 3.3V but is there anyway to change this to a lower voltage?

Thanks,

circuitbent

2

Please refer to the Xilinx Spartan-3 documentation for impedance. The XEM3001 has these pins directly attached to the header connectors with only a short PCB trace in between.

On the XEM3001, all VCCO are hardwired to +3.3VDD. Any lower voltage requirements would need to use level translators unless they are inputs and would still register high with the Xilinx input thresholds.

Note that our XEM3005, XEM3010, and XEM3050 products allow you to apply a different I/O voltage if you remove the corresponding ferrite beads.