UPGRADE YOUR BROWSER

We have detected your current browser version is not the latest one. Xilinx.com uses the latest web technologies to bring you the best online experience possible. Please upgrade to a Xilinx.com supported browser:Chrome, Firefox, Internet Explorer 11, Safari. Thank you!

AR# 13909

Virtex-II/-II Pro, XCITE/DCI - VRN is pulled up to VCCO and VRP is pulled down to GND. Is this correct?

Description

General Description:

In the Virtex-II/-II Pro User Guide, Rule #3 states that VRN must be pulled up to VCCO, while VRP must be pulled down to GND. Is this correct?

You can access this information in the Virtex-II and Virtex-II Pro User Guides by selecting "Design Considerations" -> Using Digitally Controlled Impedance (DCI) -> DCI in Virtex-II (Virtex-II Pro) Hardware:

Virtex-II Pro

1. Go to:

http://www.xilinx.com/xlnx/xweb/xil_publications_index.jsp?category=User+Guides
2. Select Virtex-II Pro under "FPGA Device Families."

3. Select Virtex-II Pro Platform FPGA User Guide.

Virtex-II

http://www.xilinx.com/xlnx/xweb/xil_publications_display.jsp?category=/User+Guides/FPGA+Device+Families/Virtex-II/&iLanguageID=1

Solution

Yes, the user guides are correct.

"P" is for the PMOS transistor's impedance. The resistor that controls the pull-up impedance of PMOS must be connected to the ground pin. Therefore, VRP must be pulled down to GND.

"N" is for the NMOS transistor's impedance. The resistor that controls the pull-down impedance of NMOS must be connected to VCCO. Therefore, VRN is pulled up to VCCO.

AR# 13909
Date Created 08/29/2007
Last Updated 12/15/2012
Status Active
Type General Article