AR #11713 - Virtex-E/-II/-II Pro - Maximum number of simultaneously switching outputs per Power/Ground pair (SSO guidelines)

AR#	11713
Part	HW-SelectIO
Last Modified	2008-10-09 00:00:00.0
Status	Active
Keywords	Virtex-II, switch, simultaneous, SSO, outputs, Virtex-E, guideline, Virtex-II Pro, Pro, recommendation

Solution

For a detailed discussion about handling SSOs, please refer to (Xilinx XAPP689), Managing Ground Bounce in Large FPGAs. The SSO guidelines pointed to below are to be used in conjunction with the methodology outlined in the Application Note.

Virtex-II Pro
Refer to the Virtex-II Pro and Virtex-II Pro X FPGA User Guide at:
http://www.xilinx.com/support/documentation/user_guides/ug012.pdf
See Simultaneous Switching Guidelines, page 201. Table 3-36 lists the maximum number of simultaneously switching outputs per Power/Ground pin pair.

Virtex-II
Refer to the Virtex-II Platform FPGA User Guide at:
http://www.xilinx.com/support/documentation/user_guides/ug002.pdf
See Simultaneous Switching Output (SSO) Guidelines, page 188. Table 3-36 lists the maximum number of simultaneously switching outputs per Power/Ground pin pair.

Virtex-E
Refer to the Detailed Functional Description data sheet at:
http://www.xilinx.com/support/documentation/data_sheets/ds022-2.pdf
Select Using Select I/O -> Design Considerations -> Simultaneous Switching Guidelines.

NOTE: The SSO guidelines for HSTL18 ( HSTL with VCCO = 1.8V) are not yet listed. For now, use the regular HSTL (with VCCO = 1.5V) guidelines and reduce by 25%. For more information on HSTL 1.8V support, refer to (Xilinx Answer 9762).