Article ID: 000080022 Content Type: Troubleshooting Last Reviewed: 09/11/2012

Are there any known issues that may cause a functional failure in APEX™ EP20K400E devices?



Critical Issue

Description Yes, there is a known issue that may cause a functional failure in APEX EP20K400E devices. Altera has identified a defect that affects four logic elements (LEs) in some EP20K400E devices. This defect causes one of the two outputs on each of the four different LEs (out of the 16,640 LEs in the device) to be non-functional. It has been isolated to the following logic elements (LEs): LC10_2_M4, LC10_3_M4, LC10_2_L4, and LC10_3_L4.

The defect prevents these LEs from driving out to the left side of the logic array block (LAB). When these LEs drive an output pin or another LE in the same LAB using local line 10, you may see functional failures and/or outputs stuck at ground. These LEs will operate normally in all other aspects, including proper implementation of logic in their look-up tables (LUTs).

Because this issue only affects one aspect of these four particular LEs, most designs will not be affected by this problem. Even so, Altera has created the following utility to determine whether your design uses these LEs and is affected by this problem.


Please note that this problem was isolated to the EP20K400E device and Altera has ensured that no other devices have similar flaws. Altera has also implemented a new test program to screen all products for this type of defect.

Altera is also evaluating options to correct this flaw on future APEX EP20K400E shipments.

Click on the following link for the EP20K400E errata sheet.

EP20K400E Programmable Logic Device Errata Sheet

The Excalibur EPXA4 devices are not affected by this problem.

Related Products

This article applies to 1 products

Apex™ 20K



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