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.

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MIL-PRF-20M

4.4.4 FRL and quality level verification.

4.4.4.1 Failure rate (FR) qualification and lot conformance FR inspection. FR qualification and lot conformance FR

inspection shall be in accordance with the general and detailed requirements of MIL-STD-690 with the following

details.

a. Procedure I: Qualification at the initial FRL. Level "M" (1.0 percent) of FRSP-90 shall apply. Sample units

that have been subjected to the qualification inspection specified in group VI, table IV shall be continued on

test as specified in 4.7.20.2.

b. Procedure II: Extension of qualification to lower FRLs. To extend qualification to the "R" (0.01 percent) FRL

and "S" (0.001 percent) FRL, data from two or more voltage groups within a style of similar construction (see

4.6.1.1.1) may be combined.

c. Procedure III: Maintenance of FRL qualification. Maintenance period B of FRSP-10 shall apply. Regardless

of the number of production lots produced during this period, the specified number of unit hours shall be

accumulated to maintain qualification.

4.5 Verification of qualification (ER styles only). Every 6 months, the manufacturer shall provide verification of

qualification to the qualifying activity. Continued qualification is based on meeting the following requirements:

b. The manufacturer has not modified the design of the item.

c. Lot rejection for group A inspection does not exceed 10 percent or one lot, whichever is greater.

d. The requirements for group B inspection are met.

e. Verification of FRLs.

f. PPM assessment.

When group B requirements were not met and the manufacturer has taken corrective action satisfactory to the

qualifying activity, group B retesting shall be instituted. A summary of the retesting shall be forwarded to the

qualifying activity within 30 days after completion of the retest.

Failure to submit the report within 30 days after the end of each 6 month period may result in loss of qualification for

the product. In addition to the periodic report, the supplier shall immediately notify the qualifying activity at any time

during the 6 month period that the inspection data indicates failure of the qualified product to meet the requirements

of this specification.

As long as the required number of maintenance hours in a group (see 4.6.1.1.1) are able to be maintained by styles

in that group, a style does not have to be produced solely for testing. The manufacturer shall certify that they retain

the capabilities and facilities necessary to produce that product. In the event that units must be manufactured for the

purpose of maintaining the required hours, they shall also undergo all required testing prior to being placed on life test

and be subjected to all group B requirements.