MIL-PRF-38535K
APPENDIX A
A.4.6.1.2 Burn-in acceptance criteria. The PDA for each inspection lot or class level S sublot submitted to burn-in
and interim (post burn-in) electrical parameters (see test method 5004 of MIL-STD-883) shall be 5 percent (or one
device, whichever is greater) on all failures. In addition, for class level S, the PDA shall be 3 percent (or one device,
whichever is greater) on functional failures. A manufacturer may elect to divide inspection lots into splits for burn-in
and interim electrical parameter measurement and calculate a PDA for each split, or the manufacturer may elect to
add all failures from the constituent splits together to calculate a PDA for the original inspection lot. If a PDA is
calculated for each split, it shall be used as accept/reject criteria for that split only and shall not be combined with the
PDA from any other lot or split for any reason related to lot or split acceptance. If a PDA is calculated for an
inspection lot by adding the failures found in the various constituent splits, this PDA shall be used as accept/reject
criteria for the entire lot and shall, in no way, be used as accept/reject criteria for any grouping of devices other than
the entire lot. Delta limits shall be defined in the device specification or drawing. When the PDA applies to delta
limits, the delta parameter values measured after burn-in (100 percent screening test) shall be compared with the
delta parameter values measured prior to that burn-in. Lots may only be resubmitted when the observed percent
defective does not exceed twice the specified PDA (10 percent) or 2 devices, whichever is greater. Any lot that
exceeds the allowable resubmission PDA, (greater than 10%, but less than 20%), the manufacturer may resubmit the
lot provided analysis is performed to a level sufficient to determine the mechanism of failure for the lot with TRB
approval and written notification (letter or email) to the Qualifying Activity prior to shipment. The lot may be
resubmitted using tightened inspection criteria. The delta criteria applying to such resubmissions shall be in
accordance with the following procedure:
a. Devices having delta drift values in excess of the device specification or drawing limits shall be rejected.
b. The remaining devices shall then be submitted to the balance of inspections and tests as specified herein.
A.4.6.1.2.1 Failure analysis of burn-in screen failures for class level S devices. Catastrophic failures (e.g., shorts
or opens measurable or detectable at +25°C) subsequent to burn-in shall be analyzed. Analysis of catastrophic
failures may be limited to a quantity and degree sufficient to establish failure mode and cause and the results shall be
documented and made available to the Government representative.
A.4.6.2 External visual screen. The final external visual screen shall be conducted in accordance with TM 2009 of
MIL-STD-883 after all other 100 percent screens have been performed to determine that no damage to, or
contamination of, the package exterior has occurred.
A.4.6.3 Particle impact noise detection (PIND) test for class level S devices. The inspection lot (or sublots) shall
be submitted to 100 percent PIND testing a maximum of five times in accordance with test method 2020 of
MIL-STD-883, condition A. PIND prescreening shall not be performed. The lot may be accepted on any of the five
runs if the percentage of defective devices is less than 1 percent (zero failures allowed for lots of less than 100
devices). All defective devices shall be removed after each run. Lots that do not meet the 1 percent PDA on the fifth
run, or exceed 25 percent defectives cumulative, shall be rejected and resubmission is not allowed.
A.4.6.4 Lead forming. When lead forming (bending) is specified for any device class, a sample fine and gross seal
test shall be performed in accordance with table IA as specified herein or test method 5004 of MIL-STD-883 after the
lead forming operations and prior to final visual inspection of these devices, and devices which fail any test shall be
removed from the lot.
A.4.6.5 Nondestructive bond pull test for class level S devices. Nondestructive 100 percent bond pull test shall be
performed for class level S devices. The total number of failed wires and the total number of devices failed shall be
recorded. The lot shall have a PDA of 2 percent or less based on the number of wires pulled in specified lot. The
test shall be performed in accordance with test method 2023 of MIL-STD-883. Devices from lots that have been
subjected to the nondestructive 100 percent bond pull test and have failed the specified class level S, PDA
requirement shall not be delivered as class level B product.
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ACTEL [ Actel Corporation ]
