Engineering Samples vs X-grade and production released products?

The terms "Engineering Sample", and "X-Grade" are defined as follows:

Engineering-Grade Samples are often first-article product.

There is usually a high probability of nonconformance to specification either in the product design or in the testing process. Product Engineering makes all reasonable effort to supply information to customers receiving samples outlining the quality status of Engineering- Grade samples. Product Engineering may serialize these samples to maintain some level of traceability to test data but this is not required. Engineering-Grade samples are intended to enable customers to gain early design application experience with the IC Product. They also serve as an informal feedback channel to the IC product characterization process. Analog Devices assumes no responsibility for the inherent quality of Engineering-Grade samples. All Engineering-Grade samples must have “ENG” branded on the device where the performance grade is typically branded. The performance grade may not be branded on the part.

X-Grade Product is truly pre-production product.

The major differences between X-Grade product and production grade product are that successful demonstration of all qualification criteria has not been met and/or final characterization of the product has not been completed. The qualification criteria may not have been met because the product failed qualification testing (in any way) or the qualification testing has not yet been completed. All X-Grade product must be tested to the released test program and must conform to all production outgoing processes and quality checks. All X-Grade IC product shall be permanently marked as such with an “X.” This “X” shall replace the product grade for IAG/CSP products and follow the performance (speed) grade on DSP products. The “X” will always appear on the top side of the IC package. X-Grade product quality is guaranteed to meet all Production quality requirements except for the waiver of those quality parameters agreed to by the particular customer(s) in the X-Grade agreement. An X-Grade agreement must be signed by the customer for all X-Grade purchases in accordance with the limit set by the product manager in the order entry description.

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