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AR# 36073

MIG Virtex-6 DDR3/DDR2 - Why is the maximum data width 120-bits for HXT devices?

Description

MIG does not allow data width selection for HXT devices above 120-bits.

Why do other devices allow a maximum data width of 144-bit but HXT is set to 120-bits?

Solution

HXT devices only have 2 inner I/O bank columns.

Due to the design's usage of regional clocks,  
MIG requires 3 rows of banks to place a controller .

Two inner columns with three rows, results in six I/O banks for a MIG controller.

One bank will be used for Addr/Cont which only leaves five banks for data.

Three Data bytes fit into a bank which means that MIG can only fit 120-bits of data (15-bytes * 8 = 120-bits) in HXT devices.
AR# 36073
Date Created 06/08/2010
Last Updated 08/26/2014
Status Active
Type General Article
Devices
  • Virtex-6 HXT
IP
  • MIG