This is to advise you that a Design and/or Process Change will be made to the following High Reliability product(s):
Product ID (Description): FACT S Level Logic Products - QML Class V, JAN Class S, and Standard MLS
Proposed Date of Change: AUGUST 1998
Description of Change: FACT S LEVEL STATIC BURN-IN REDUCTION - REMOVAL OF STATIC LOW BURN-IN
National Semiconductor's TRB and DSCC have approved changes to the burn-in flow used on FACT S Level products, allowing removal of Static Low burn-in. The previous burn-in flow, which was based on SMDs and slashsheets, has two Static burn-ins: 1) Static Low, during which inputs are tied to Ground. 2) Static High, during which inputs are tied to VCC. Analysis of all Static Low burn-in failures collected over a four month period found no units that would not also have failed Static High burn-in. (The number of failures was eight in 11,500 units tested.)This is evidence that Static Low burn-in can be eliminated without affecting product reliability. Static Low burn-in can be reactivated based upon a 2.5% PDA (Percent Defective Allowable)that is being implemented as part of the new flow. Lots with more than 2.5% Static High burn-in failures will be submitted to Static Low burn-in with analysis performed on all failures. This will ensure that lots with greater than expected numbers of failures will still receive, as a minimum, two Static burn-ins. This change applies to all standard FACT S level products - QML Class V, JAN Class S, and Standard MLS. Standard MLS products have S level processing, but no source control drawing. This change does not apply to MLS products where a source control drawing exists, unless the drawing specifies this reduced burn-in flow. Effect of Change: Quality and reliability with the new burn-in flow will be equal to or better than with the previous burn-in flow.
Associated Notes / Table(s):
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