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

4.8.20 High temperature exposure (see 3.25).

Mounting: Not required.

Initial measurements: DC resistance shall be measured as specified in 4.8.5 at 25 C �2 C.

Procedure: Following initial resistance measurements, networks shall be placed in a chamber with forced

air circulation maintained at 125OC �5OC for a period of 100 hours �4 hours with no load applied.

Final measurements: After removal from the test chamber, networks shall be permitted to stabilize at an

ambient temperature of 25 C �5 C. Resistance measurements shall be made as specified in 4.8.5.

Networks shall be inspected for evidence of mechanical damage.

4.8.21 Low temperature storage (see 3.26).

Mounting: Not required.

Procedure: DC resistance shall be measured as specified in 4.8.5. Within 1 hour after this measurement,

the networks shall be placed in a cold chamber at -65 C +0 C, -3 C. Twenty-four hours after the networks

have reached this temperature, the temperature of the chamber shall be gradually increased to room

temperature within a period of not more than 8 hours. The networks shall be removed from the chamber

and at a temperature of 25OC �5OC, the dc resistance shall then be measured as specified in 4.8.5.

Networks shall be inspected for evidence of mechanical damage.

4.8.22 Hermetic seal (applicable to characteristic C) (see 3.27). Networks shall be tested in accordance with

method 112 of MIL-STD-202. The following details shall apply:

Test condition C, procedure IIIa or IIIb of method 112, MIL-STD-202 shall be used.

Gross leak test: Test condition D.

4.8.23 Steady-state humidity (see 3.28). Networks shall be tested at a steady state humidity condition of

85 C �3 C, 85 percent �5 percent relative humidity for a period of 1,000 hours +96 hours, -0 hours. The following

details and exceptions shall apply:

Mounting: Method B (see 4.8.1.2).

Initial measurement: Same as 4.8.16b.

Loading voltage: Same as 4.8.16c.

Interval measurement is at 1,000 hours +96 hours, -0 hours. The networks will be allowed to stabilized to

room ambient conditions prior to any electrical measurement.

Final measurements: Same as 4.8.16f.

Inspection after test: Same as 4.8.16g.

4.8.24 Bond pull (applicable to configuration C of styles RNS030 and RNS040) (see 3.29). Networks shall be

mounted as specified in 4.8.1.2, method B. Pull tester/gauge and hook, (HMP model, with a 0 gram to 15 gram scale

or equivalent) shall be used. All wire bonds are to be visually inspected to confirm acceptability prior to pull test

(see 3.5.5). Four bonding pads shall be randomly selected and shall be subjected to the bond pull test as specified.

The pull test is applied by inserting the hook under the loop of the bonding wire and with the substrate held down, the

pulling force is applied approximately at the center of the loop for 30 seconds minimum at a minimum force of 6

grams