AR# 8725

Virtex/-E - What is the strength of the internal pull-up or pull-down resistors in the Virtex/-E I/O blocks?

What is the strength of the internal pull-up or pull-down resistors in the Virtex/-E I/O blocks?

The maximum strength (lowest resistance) is defined by Irpu and Irpd in the DC and Switching Characteristic Data Sheet.

The Virtex Data Sheet can be found at:
http://www.support.xilinx.com/xlnx/xweb/xil_publications_display.jsp?sGlobalNavPick=&sSecondaryNavPick=&category=-18777&iLanguageID=1

The Virtex-E Data Sheet can be found at:
http://www.support.xilinx.com/xlnx/xweb/xil_publications_display.jsp?sGlobalNavPick=&sSecondaryNavPick=&category=-18776&iLanguageID=1

The pull-up resistor will range from 13.2K to 100K Ohms. The strength of the pull-up will decrease as VCCO decreases (resistor value increases). The strength of the pull-down will have the opposite affect when VCCO decreases. As VCCO decreases, the strength of the pull-down increases (resistor value decreases). In either case, the pull-up or pull-down resistor range is sufficient to either hold a logic level High or logic level Low.

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