MIL-PRF-20 Capacitor, Fixed, Ceramic Dielectric \(Temperature Compensating\), Established Reliability And Non-Established Reliability, General Specification ForThis specification covers the general requirements for established reliability \(ER\) and non-ER, temperature compensating, fixed capacitors for use primarily where compensation is necessary for circuit applications due to temperature changes, in bypass and coupling applications. Capacitors meeting the ER requirements specified herein have a failure rate level \(FRL\) ranging from 1.0 percent per 1,000 hours to 0.00l percent per 1,000 hours. These failure rate levels are established at a 90-percent confidence level based on the life test parameters specified and are maintained at a 10-percent producer\'s risk. An acceleration factor of 8:1 has been used to relate the life test data at 200 percent of rated voltage at the applicable high test temperature to the rated voltage at the applicable high test temperature. A part per million \(ppm\) quality system is used for documenting and reporting the average outgoing quality of ER capacitors supplied to this specification. Statistical process control \(SPC\) techniques are required in the manufacturing process to minimize variation in production of ER capacitors supplied to the requirements of this specification.

Pages 1 - 2 - 3 - 4 - 5 - 6 - 7 - 8 - 9 - 10 - 11 - 12 - 13 - 14

MIL-PRF-20M

TABLE VI. Sampling plans for subgroup 2.

Lot size

Sample size

100%

14 -

150

151 -

280

281 -

500

501 - 1,200

1,201 - 3,200

3,201 - 10,000

10,001 - 35,000

35,001 - 150,000

150,001 - 500,000

500,001 - Up

102

4.6.1.2.1.2 Subgroup 2

4.6.1.2.1.2.1 Sampling plan. Subgroup 2 tests shall be performed on an inspection lot basis. Samples subjected

to subgroup 2 shall be selected in accordance with table VI based on the size of the inspection lot. In the event of

one or more failures, the lot shall be rejected.

4.6.1.2.1.2.2 Rejected lots. The rejected lot shall be segregated from new lots and those lots that have passed

inspection. The rejected lot shall be 100 percent inspected for those quality characteristics found defective in the

sample and any defectives found removed from the lot. A new sample of parts shall then be randomly selected in

accordance with table VI. If one or more defects are found in this second sample the lot shall be rejected and shall

not be supplied to this specification.

4.6.1.2.1.3 Subgroup 3 (solderability).

4.6.1.2.1.3.1 Sampling plan. Five samples shall be selected randomly from every inspection lot and subjected to

the solderability test. The manufacturer may use electrical rejects from the subgroup 1 screening tests for all or part

of the samples to be used for solderability testing. If there are one or more defects, the lot shall be rejected.

4.6.1.2.1.3.2 Rejected lots. In the event of one or more defects, the manufacturer may use one of the following

options to rework the lot:

a. Each production lot that was used to form the failed inspection lot shall be individually submitted to the

solderability test as required in 4.6.1.2.1.3.1. Production lots that pass the solderability test are available for

shipment. Production lots failing the solderability test can be reworked only if submitted to the solder dip

procedure in 4.6.1.2.1.3.2b.

b. The manufacturer shall submit the failed lot to a 100 percent solder dip process in accordance with appendix

A. Two hundred sample units from this lot shall then be subjected to all group A, subgroup 1 post-electrical

tests, with no defects allowed.

(1) If the 200 sample units (or 100 percent of the lot, whichever is less) pass the group A, subgroup 1

post-electrical tests, 5 additional units shall then be subjected to the solderability test, with no defects

allowed. If there are one or more defects, the lot shall be considered rejected and shall not be furnished

against the requirements of this specification.