MIL-PRF-914 Resistor Networks, Fixed, Film, Surface Mount, Nonestablished Reliability, And Established Reliability, General Specification ForThis specification covers the general requirements for nonestablished reliability \(non-ER\) and established reliability \(ER\), hermetically sealed \(see 3.27\) and nonhermetically sealed networks \(see 3.27.1\). These networks consist entirely of fixed, film resistors. They are primarily intended for use in surface mount applications where space is a major concern. ER resistors covered by this specification will have life failure rates \(FR\) ranging from 1 percent to 0.001 percent per 1,000 hours \(see 1.2.1.7\). The ER FR are established at a minimum 60-percent confidence level on the basis of life tests. Designers are CAUTIONED on using these resistors in pulse applications \(see 6.4.4\).

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MIL-PRF-914C

4.8.16 Moisture resistance (see 3.21). Networks shall be tested in accordance with method 106 of MIL-STD-202.

The following details and exceptions shall apply:

Mounting: Method B (see 4.8.1).

Initial measurement: Immediately following the initial conditioning period, dc resistance of resistors in the

network shall be measured as specified in 4.8.5.

Loading voltage: A dc voltage equivalent to 0.100 of rated wattage not to exceed the maximum rated

voltage (see 3.1) shall be applied to all resistor elements during the first 2 hours of step 1 and step 4.

Subcycle: Step 7b shall not be applicable. Step 7a shall be performed during any five of the first eight

cycles only.

Measurements at high humidity: None.

Final measurements: Upon completion of step 6 of the final cycle, the resistor networks shall be removed

from the chamber and within 8 hours, the dc resistance, dielectric withstanding voltage, and insulation

resistance shall be measured in accordance with 4.8.5, 4.8.13, and 4.8.14, except that dielectric

withstanding voltage and insulation resistance may be performed without the bottom metal plate of figure 4

and figure 5. When the networks are tested as specified, the change in resistance between initial and final

measurements shall not exceed the value specified in 3.21.

Inspection after test: Networks shall be inspected for evidence of mechanical damage.

4.8.17 Shock (specified pulse) (see 3.22). Networks shall be tested in accordance with method 213 of

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

Special mounting means: Leaded components shall be mounted by rigidly restraining the leads; leadless

chip carrier packages shall be mounted by (soldering, clamping, etc.) restraining the body.

Test leads: Test leads used during this test shall be no larger than AWG size 22 stranded wire, so that the

influence of the test lead on the resistor shall be held to a minimum. The test lead length shall be no longer

than necessary.

Measurements before shock: Resistance shall be measured as specified in 4.8.5.

Test condition I.

Measurements after shock: Resistance shall be measured as specified in 4.8.5.

Inspection after shock: Networks shall be inspected for evidence of mechanical damage.

4.8.18 Vibration, high frequency (see 3.23). Networks shall be tested in accordance with method 204 of

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

Mounting: As specified in 4.8.17a.

Test leads: As specified in 4.8.17b.

Measurements before vibration: As specified in 4.8.17c.

Test condition D.

Measurements after vibration: As specified in 4.8.17e.

Inspection after vibration: Networks shall be inspected for evidence of mechanical damage.