Xilinx would like to highlight some of the pitfalls and dangers associated with services offered by some after market companies.

"Up-screening" is a practice whereby attempts are made to elevate the grade level of an IC through the application of post-sale testing and/or screening. For example, a popular approach is to take commercial (C grade) products and test them at a higher temperature to obtain "I" and "M" grade components. The difference between the various levels of grading involves many variables including operating voltage ranges, leakage current, and speed margins, as well as temperature guardbands.

Development of reliable methodologies and test suites for Programmable Logic Devices (PLDs) requires specialized expertise and large investments. The practice of simply re-testing Xilinx product to some test program that does not test all the operating modes is not effective, or reliable. Very few after-market test houses have the required hardware implementation and none have Xilinx methodology.

Furthermore, Xilinx products are extremely complex, and can be damaged by the application of inappropriate configuration fields, voltage or current stresses. Any third party attempting to test Xilinx devices must have an intimate knowledge of our architecture, circuit implementation, and design methodology. Without this expertise it is practically impossible to write safe, efficient test code.

Another practice is to test and certify commercial product outside the manufacturer's maximum ratings. This practice is extremely dangerous. Commercial products must not be used outside their published design ratings. Please be advised that Xilinx can not be responsible for any component or system failure, as a result of its products being used outside of Xilinx published operating parameters and can not warrant any component that has been subjected to "up-screening".

Xilinx takes great care in the selection of its technology partners and distributors, through a formal qualification process involving ongoing monitoring and measurement. It is in the best interest of you, the customer, to only purchase Xilinx products from approved sources. Please contact your local Xilinx Sales Representative if in doubt.