MIL-PRF-38535K
APPENDIX A
A.3.5.5.3 Internal lead wires. Internal lead wires or other conductors which are not in thermal contact with a
substrate along their entire length (such as wire or ribbon conductors) shall be designed to experience, at maximum
rated current, a continuous current for direct current, or a root mean square (RMS) current (peak current divided by
√2), for alternating or pulsed current, not to exceed the values established by the following relationship:
I = Kd 3/2
Where: I = Maximum allowed current in amperes.
d = Diameter in inches for round wire (or equivalent round wire diameter which would provide the
same cross-sectional area for other than round wire internal conductor).
K = A constant taken from table A-IA below for the applicable wire or conductor length and
composition used in the device.
Composition
"K" values for bond-to-bond total conductor length
Length > 0.040 inch (0.10 cm)
Length ≤ 0.040 inch (0.10 cm)
Aluminum
Gold
Copper
Silver
22,000
30,000
30,000
15,000
9,000
15,200
20,500
20,500
10,500
6,300
All other
A.3.5.5.4 Verification of glassivation layer integrity. Where the current density of aluminum metallization for a
device type to be qualified exceeds the allowable current density for unglassivated aluminum, the device type shall be
subjected to and pass the requirements of TM 2021 of MIL-STD-883 prior to qualification and the glassivation layer
integrity sample used along with and a photograph of the etched die shall be documented and maintained. One
resubmission is permitted at twice the sample size. Unless otherwise specified by the qualifying activity (QA), the
device type shall be tested after sealing (or after exposure to the time/temperature sealing profile) in the package
type that receives the highest temperature range during sealing for which the device type is to be qualified. Changes
in design, materials, or process, which affect current density or glassivation, shall also be evaluated using TM 2021 of
MIL-STD-883. This evaluation applies only when the current density requirements for unglassivated aluminum are
exceeded.
A.3.5.6 Package element material and finish.
A.3.5.6.1 Package material. Package body material shall be metal, glass, or ceramic in accordance with A.3.5.1.
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ACTEL [ Actel Corporation ]
