MIL-PRF-28776 Relays, Hybrid, Established Reliability, General Specification ForThis specification establishes the general requirements for relays that use a combination of solid state circuit input elements functioning with an electro-mechanical relay that performs the switching functions associated with control system applications \(see 6.1\). These relays are designed to operate in low and medium power switching circuits with contact ratings up to 1 ampere alternating current \(ac\) or direct current \(dc\). The failure rate level is established at a confidence level of 90 percent for qualification and 60 percent for maintenance of qualification based on 100,000 cycles at +125┬░C under rated load conditions specified herein. Excludes time delay relays. CAUTION: The use of any coil voltage less than the rated coil voltage will compromise the operation of the relay. CAUTION: Pick-up, hold, and dropout voltages are for test purposes only and are not to be used as design criteria. For additional application and caution information, see 6.1.

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MIL-PRF-28776F

3.8 Solderability (see 4.8.3). The critical (examination) area of solid wire lead and pin terminals shall be at least 95

percent covered with a continuous new solder coating in accordance with method 208 of MIL-STD-202. For solder-

lug terminals greater than .045 inch (1.14 mm) in diameter, 95 percent of the total length of fillet, which is between the

standard wrap wire and the terminal, shall be tangent to the surface of the terminal being tested, and shall be free of

pinholes and voids. A ragged or interrupted line at the point of tangency between the fillet and the terminal under test

shall be considered a failure.

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3.9 Seal (see 4.8.4). The standard leak rate (L value in Eq (1) of MIL-STD-883 Method 1014) shall be 1 x 10

atm cm 3/s of air.

3.10 Insulation resistance (see 4.8.5). Unless otherwise specified (see 3.1), the insulation resistance shall be

10,000 megohms or more. After the high level life tests, the insulation resistance shall be 1,000 megohms or more.

3.11 Dielectric withstanding voltage (see 4.8.6). There shall be no leakage current in excess of 100 microamperes

(�A). After high level life tests, the dielectric withstanding voltage measured at atmospheric or reduced barometric

pressure shall be at least 75 percent of the initial value (3.1).

3.12 Electrical characteristics (see 4.8.7). The following tests as specified in 3.12.1 through 3.12.8 shall comprise

the electrical characteristics tests. Unless otherwise specified, electrical characteristics shall be 100 percent

inspected and performed in the order as shown below.

3.12.1 Static contact resistance or contact voltage drop (see 4.8.7.1). Unless otherwise specified (see 3.1), the

static contact resistance shall not exceed 0.05 ohm or contact voltage drop as specified (see 3.1).

3.12.2 Specified pickup, hold, and dropout values (voltages), control signal on (see 4.8.7.2). The specified pickup,

hold, and dropout values (voltages) shall be as specified (see 3.1).

3.12.3 Coil current and coil resistance (see 4.8.7.3).

3.12.3.1 Coil current (see 4.8.7.3.1). The coil current shall be as specified (see 3.1).

3.12.3.2 Coil resistance (see 4.8.7.3.2). Coil resistance of hybrid relays is not directly measurable at the relay

terminal due to resistance of drivers.

3.12.4 Turn-on (voltage or current) (coil supply voltage on) (see 4.8.7.4). 1/ The turn-on voltage shall be as

specified (see 3.1).

3.12.5 Turn-off voltage (coil supply voltage on) (see 4.8.7.5). The turn-off voltage shall be as specified (see 3.1).

3.12.6 Turn-on time and turn-off time (see 4.8.7.6). The turn-on time and turn-off time shall be as specified (see

3.1). In multipole relays, during each of the turn-on and the turn-off time measurements, the difference between the

first moving contact to make and the last moving contact to make shall not exceed 1 millisecond (ms).

3.12.6.1 Break before make (see 4.8.7.6.1). Moving contacts within a multipole relay shall show no evidence of

any open contact closing before all closed contacts have opened (see 3.1). This applies to either state of the relay.

3.12.7 Contact dynamic characteristics (see 4.8.7.7).

3.12.7.1 Contact bounce (applicable to failure rate level "L") (see 4.8.7.7.1). Unless otherwise specified (see 3.1),

the duration of the contact bounce shall not exceed 1.5 ms.

3.12.7.2 Contact stabilization time (applicable to failure rate levels "M", "P", and "R") (see 4.8.7.7.2). Unless

otherwise specified (see 3.1), the time to reach and maintain a static contact resistance state shall not exceed 2.0

ms.

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1/ Wherever "voltage" is used herein, it is considered to include "current" if applicable.