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# 36364

Spartan-6 - What is the -3N speed grade?


The Spartan-6 FPGA family supports a device with a -3N speed grade. What is -3N?


The Spartan-6 LX and LXT devices with -3N speed gradedo not have the Memory Controller Block (MCB) support. The -3N speed files are independent and different than the -3 speed files, so all timing analysis must be done completely for the targeted device. See the Switching Characteristics section of the Spartan-6 FPGA Data Sheet(DS162) for the speed file numbers.

Software Support

In the ISE12.3 software, there isa -3N speed grade available to pick for the target device.

Software versions prior to the ISE 12.3 softwaredo not have a -3N speed grade available to use.Instead, target the -3 speed grade and do not use the Memory Controller Block.The generated bitstream created will still work correctly in the -3N speed grade devices.However, beginning in ISE tools 12.4, the -3 and -3N speed grades are no longer identical, so the -3N devices must beselected in the software if they are being targeted by the design.

Other Notes

  • Do not usethe Memory Interface Generator (MIG) or the Multi Port Memory Controller (MPMC) through EDK for any -3N speed grade parts. When targeting a -3N speed grade part in the ISE 12.3 software and later, the DRC will error out if an MCB is used in the design.
  • -3N is marked "N3C" or"N3I", with the "C" or "I" designating temperature rating.
  • -3N will apply to all devices except those that do not support MCBs in the standard -3 speed grade: LX4 device, TQG144 package, and CPG196 package.
  • There are no, and will not be any, -2N devices.

Linked Answer Records

Associated Answer Records

Answer Number Answer Title Version Found Version Resolved
40532 MIG Spartan-6 MCB - FPGA Device support N/A N/A
AR# 36364
Date Created 07/13/2010
Last Updated 12/15/2012
Status Active
Type General Article
  • Spartan-6 LX
  • Spartan-6 LXT
  • ISE Design Suite - 12.3
  • ISE Design Suite - 12.4
  • ISE Design Suite - 13.1
  • ISE Design Suite - 13.2