DLA - MIL-DTL-32139B (1)
CONNECTORS, ELECTRICAL, RECTANGULAR, NANOMINIATURE, POLARIZED SHELL, GENERAL SPECIFICATION FOR
|Publication Date:||13 April 2021|
This specification covers the detail requirements for nanominiature connectors terminated on printed circuit boards or attached to cable assemblies. The connector contacts are densely packed with .025 (0.64 mm) inch spacing between contact centers in the same row. These connectors are intended for use in assemblies requiring very densely packaged electronic components and are commonly used in digital applications.
These connectors are intended for use for interconnections on printed wiring board, printed wiring board to cable, cable to panel, or cable to cable on miniaturized equipment sub-assemblies with... View More
These connectors are intended for use for interconnections on printed wiring board, printed wiring board to cable, cable to panel, or cable to cable on miniaturized equipment sub-assemblies with low power requirements. The connectors covered by this specification are militarily unique because of requirements to operate satisfactorily under sinusoidal vibrations of 10 to 2000 Hz at up to 20 g's; withstand 48 hours of salt spray without exposure of base metals which will affect performance, or cause pitting or porosity of the finish; withstand 100 g's of shock with no electrical discontinuity; and operate at temperatures of minus 55 to plus 125 degrees Celsius. Commercial electronic components are not designed to withstand these extreme conditions or sudden environmental changes, and would experience catastrophic failure.
Space applications using aluminum shells.
Aluminum shells with electroless nickel are intended for space applications. Cadmium plating is normally prohibited on electrical, electronic and electromechanical (EEE) parts and associated hardware. In space applications, cadmium plating may be acceptable when specifically approved for the intended use. Cadmium plating is commonly used on connectors, connector hardware and mechanical hardware such as fasteners. It provides excellent resistance to salt corrosion and is therefore offered in many military specifications predominantly for use in naval applications. However, most NASA applications are not concerned with salt corrosion and the risks associated with use of cadmium plating noted above outweigh the benefits of its use in space applications.
a. Cadmium is known to sublimate in a hard vacuum environment (especially at temperatures above 75°C). The sublimation products, which are conductive, can redeposit resulting in short circuits. The sublimation products may also interfere with sensitive optics.
b. Cadmium is a toxic material that should not be used in manned spaceflight applications.
c. Cadmium is subject to the spontaneous growth of cadmium whiskers.
Corrosion has been experienced on connectors prewired with SAE AS22759/33, SAE AS22759/51 and SAE AS22759/52 wires and stored in a sealed environment. CAUTION SHOULD BE EXERCISED WHEN USING THIS WIRE.View Less