MILPRF55110G
APPENDIX A
A.3.7.5
A.3.7.5 Electrical requirements (see IPC9252 for additional guidelines).
A.3.7.5.1
A.3.7.5.1 Circuit continuity. The circuit continuity test shall be in accordance with A.4.8.5.1. For qualification
inspection there shall be no circuit whose resistance exceeds 20 ohm. Unless otherwise specified (see A.3.1.1), for
referee purposes, 0.1 ohm maximum per inch of circuit length shall apply. Circuits that consist of long runs of narrow
conductors or short runs of very wide conductors may increase or decrease the resistance. The acceptability of these
type of circuits, of controlled impedance nets, or of designed resistive patterns shall be specified on the master
drawing (see A.3.1.1).
A.3.7.5.2
A.3.7.5.2 Circuit shorts. When tested as specified in A.4.8.5.2, the resistance between mutually isolated
conductors shall be greater than 2 megohms.
A.3.7.5.3
A.3.7.5.3 Dielectric withstanding voltage (DWV). When tested as specified in A.4.8.5.3, there shall be no
flashover, sparkover, or dielectric breakdown.
A.3.7.5.4
A.3.7.5.4 Heatsink planes or metal core printed boards. When designs with heatsink planes or metal cores are
inspected as specified in A.4.8.5.2, the dielectric material used to insulate the heatsink plane or metal core from the
conductor pattern and plated through holes shall provide an insulation resistance greater than 2 megohm. The
printed board shall be capable of withstanding the specified voltage between the conductor pattern or plated-through
holes and the heat sink plane. During the test there shall be no flashover, sparkover, or dielectric breakdown.
A.3.7.6
A.3.7.6 Environmental requirements.
A.3.7.6.1
A.3.7.6.1 Moisture and insulation resistance (MIR).
A.3.7.6.1.1
A.3.7.6.1.1 Non-flush conductor printed boards. When tested as specified in A.4.8.6.1, the printed wiring board
test specimen shall have a minimum of 500 megohms of resistance between conductors when tested at 500 volts
(+25, 0) direct current. After the test, the specimen shall be inspected in accordance with A.4.8.1 and the specimen
shall not exhibit blistering, measling, or delamination in excess of that allowed in A.3.5.1.3.
A.3.7.6.1.2
A.3.7.6.1.2 Flush conductor printed boards. When tested as specified in A.4.8.6.1.1, the printed wiring board
designed for flush conductor applications shall have a minimum of 50 megohms of resistance between conductors
when tested at 500 volts (+15, 0) direct current. After the test, the specimen shall be inspected in accordance with
A.4.8.1 and the specimen shall not exhibit blistering, measling, or delamination in excess of that allowed in A.3.5.1.3.
A.3.7.6.2
A.3.7.6.2 Thermal shock.
A.3.7.6.2.1
A.3.7.6.2.1 Thermosetting resin base materials (see A.7.6.1). While undergoing the test specified in A.4.8.6.2.1, a
resistance change of 10 percent or more between the first and last high temperature measurements shall be
considered a reject. After the test, the printed wiring board test specimens shall meet the following requirements:
a.
External visual and dimensional inspection (all types): When inspected as specified in A.4.8.1, there shall be
no evidence of plating cracks, blistering, or delamination in excess of that allowed in A.3.5.1.3.
b.
Internal visual and dimensional inspection (type 3): When the printed wiring board test specimen is
microsectioned and inspected in accordance with A.4.8.2, the requirements specified in A.3.6 shall be met.
A.3.7.6.2.2
A.3.7.6.2.2 Thermoplastic resin base materials (see A.7.6.2). While undergoing the test specified in A.4.8.6.2.2, a
resistance change of 10 percent or more between the first and last high temperature measurements shall be
considered a reject. After the test, when printed wiring board test specimens are inspected as specified in A.4.8.1,
the shall be no evidence of plating cracks, blistering, or delamination in excess of that allowed in A.3.5.1.3.
20
For Parts Inquires submit RFQ to Parts Hangar, Inc.
© Copyright 2015 Integrated Publishing, Inc.
A Service Disabled Veteran Owned Small Business