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

4.7.5 Dielectric withstanding voltage (see 3.9). Capacitors shall be tested in accordance with method 301 of

MIL-STD-202. The following details shall apply:

a. Magnitude and nature of test voltage: 300 percent of the dc rated voltage.

b. Duration of application of test voltage: 5 seconds �1 second.

c. Points of application of test voltage: Between the capacitor-element terminals.

d. Limiting value of surge current: Shall not exceed 50 mA.

e. Examination after test: Capacitors shall be examined for evidence of damage and breakdown.

4.7.5.1 Body insulation (qualification only). Capacitors shall be tested in accordance with one of the following, as

specified.

a. Test I: Capacitors shall be placed in the trough of a V-block which shall extend beyond the ends of the body

of the capacitor. A dc potential of 1,300 volts shall then be applied between the two leads connected together

and the V-block for a period of 5 seconds �1 second. The surge current shall not exceed 50 mA.

b. Test II: Capacitors shall be wrapped with a conductive tape or foil so that the conductive tape or foil shall not

be less than .0625 inch (1.59 mm) and not more than .125 inch (3.18 mm) away from the lead wires. A dc

potential of 1,300 volts shall be applied between the two leads connected together and the tape or foil for a

period of 5 seconds �1 second. The test circuit shall be so arranged that the surge current does not exceed

50 mA.

After the test, capacitors shall be examined for evidence of damage or breakdown.

4.7.6 Barometric pressure (reduced) (qualification only) (see 3.10). Capacitors shall be tested in accordance with

method 105 of MIL-STD-202. The following details and exceptions shall apply:

a. Method of mounting: Securely fastened by suitably clamping their leads.

b. Test condition B.

c. Test during subjection to reduced pressure: 100 percent of the dc rated voltage (see 3.1) shall be applied

between the capacitor-element terminals for a period of 5 seconds �1 second. The surge current shall not

exceed 50 mA.

4.7.7 Insulation resistance (see 3.11).

4.7.7.1 At +25�C. Capacitors shall be tested in accordance with method 302 of MIL-STD-202. The following

details shall apply:

a. Test potential: Rated voltage (see 3.1).

b. Points of measurement: Between capacitor-element terminals.

c. Electrification time: 2 minutes �5 seconds, except during conformance inspection when electrification time

may be the time required by the capacitor to reach full charge, provided it does not exceed 2 minutes.

Voltage shall be applied through a resistor that will limit the charging current from 30 mA to 50 mA.

4.7.7.2 At high ambient temperature. Capacitors shall be subjected to the applicable high ambient temperature

(see 3.1) for a period of time sufficient to reach thermal stability, and the insulation resistance shall then be measured

as specified in 4.7.7.1.