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 \(see 6.4.4\).

Pages 1 - 2 - 3 - 4 - 5 - 6 - 7 - 8 - 9 - 10

MIL-PRF-914C

4.8 Methods of inspection.

4.8.1 Network handling procedures.

4.8.1.1 Method A. When specified herein, the networks shall be unmounted or tested using pressure type

contacts. The test fixture shall be such that it shall not be the cause of, nor contribute to, any failure of the network in

any test for which it may be used.

4.8.1.2 Method B. When specified herein, the networks shall be mounted on test boards of fiberglass base,

nominally .0625 inch (1.589 mm) thick. Mounting accomplished with either Sn60A or Sn63A solder shall be in

accordance with J-STD-006. After mounting, the boards must be thoroughly cleaned to remove all traces of flux

residue by an appropriate cleaning method, then oven dried for 5 minutes minimum at 125OC �10OC. The test board

and mounting procedure shall be such that it shall not be the cause of, nor contribute to, any failure of a network in

any test for which it may be used. If more than one network is placed on a given test board, the networks shall be

spaced a minimum of 1.00 inch (25.4 mm) from each other.

4.8.2 Visual and mechanical inspection. Networks shall be inspected to verify that the materials, design,

construction, physical dimensions, and workmanship are in accordance with the applicable requirements

(see 3.1, 3.4 through 3.5.2 inclusive, and 3.31 through 3.31.4 inclusive).

4.8.3 Thermal shock (see 3.8). Networks shall be tested in accordance with method 107 of MIL-STD-202. The

following details and exception shall apply:

Mounting: As specified in 4.8.1, method A.

Measurement before cycling: DC resistance shall be measured as specified in 4.8.5.

Test condition: For group A inspection and qualification group I, test condition B. For qualification group V

and group C inspection, test condition B-1.

Measurement after cycling: Within 3 hours after stabilization at room temperature, dc resistance shall be

measured as specified in 4.8.5. For group A inspection and qualification group I, dc resistance shall be

measured following the test of 4.8.4.

Following the test, the networks shall be inspected for evidence of mechanical damage.

4.8.4 Power conditioning (see 3.9). Networks shall be tested in accordance with method 108 of MIL-STD-202.

The following details and exceptions shall apply:

Mounting: As specified in 4.8.1, method A.

Test temperature and tolerance: 25 C, +20 C, -5 C.

Initial measurements: Measurements may be made inside or outside the chamber.

(1) Inside chamber: When measurements are to be made inside the chamber, the initial dc resistance shall

be measured, at the applicable test temperature, after temperature stabilization, and within 8 hours of

exposure of the networks to the test temperature. This initial measurement shall be used as the

reference temperature for all subsequent measurements under the same conditions.

(2) Outside chamber: When measurements are to be made outside the chamber, the initial dc resistance

shall be measured at room temperature. This initial measurement shall be used as the reference

temperature for all subsequent measurements under the same condition.