MIL- STD-883F 2004 TEST METHOD STANDARD MICROCIRCUITS - 第391页

MIL-STD-883F METHOD 2026 25 August 1983 3 FIGURE 2026-1. Test c onditi on I, random vi brati on test -cur ve envelope (s ee table I ) . TABLE I. Val ues for test c onditi on I . 1/ Charact eris tic s Test condit ion lett…

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MIL-STD-883F
METHOD 2026
25 August 1983
2
b. Distribution curves. A probability density-distribution curve may be obtained and compared with a
gaussian-distribution curve. The experimentally-obtained curve should not differ from the gaussian curve by more
than ±10 percent of the maximum value.
2.2 Monitoring
. Monitoring involves measurements of the vibration excitation and of the test-item performance. When
specified, the device shall be monitored during the test. The details of the monitoring circuit, including the method and
points of connection to the specimen, shall be specified.
2.2.1 Vibration input
. The vibration magnitude shall be monitored on a vibration machine, on mounting fixtures, at
locations that are as-near as practical to the device mounting points. When the vibration input is measured at more than
one point, the minimum input vibration shall be made to correspond to the specified test curve (see figures 2026-1 and
2026-2). For massive test-items and fixtures, and for large-force exciters or multiple-vibration exciters, the input-control
value may be an average of the average magnitudes of three or more inputs. Accelerations in the transverse direction,
measured at the test-item attachment points, shall be limited to 100 percent of the applied vibration.
3. PROCEDURE
. The device(s) shall be rigidly fastened on the vibration platform and the leads adequately secured.
The vibration machine shall then be operated and equalized or compensated to deliver the required random frequencies and
intensities conforming to the curves specified in test condition I, figure 2026-1 or test condition II, figure 2026-2. The
device(s) shall be subjected to a random vibration specified by the test condition letter (see tables I and II) for a duration of
15 minutes in each of the orientations X, Y, and Z. Where this test is performed as part of a group or subgroup of tests, the
post-test measurements or inspections need not be performed specifically at the conclusion of this test.
3.1 Examination
. After completion of the test, an external visual examination of the marking shall be performed without
magnification or with a viewer having a magnification no greater than 3X and a visual examination of the case, leads, or
seals shall be performed at a magnification between 10X and 20X. This examination and any additional specified
measurements and examination shall be made after completion of the final cycle or upon completion of a group, sequence,
or subgroup of tests which include this test.
3.2 Failure criteria
. After subjection to the test, failure of any specified measurement or examination (see 3 and 4),
evidence of defects or damage to the case, leads, or seals, or illegible markings shall be considered a failure. Damage to
marking caused by fixturing or handling during tests shall not be cause for device rejection.
4. SUMMARY
. The following details shall be specified in the applicable acquisition document:
a. Test condition (see 3).
b. Measurements after test (see 3 and 3.1).
c. Test condition I or II and letter (A-K).
d. Test duration if other than specified.
e. Requirement for test to be conducted with device powered up, when applicable.
MIL-STD-883F
METHOD 2026
25 August 1983
3
FIGURE 2026-1. Test condition I, random vibration test-curve envelope (see table I)
.
TABLE I. Values for test condition I
. 1/
Characteristics
Test
condition
letter
Power
spectral
density
Overall
rms G
A
B
C
D
E
F
G
H
J
K
.02
.04
.06
.1
.2
.3
.4
.6
1.0
1.5
5.2
7.3
9.0
11.6
16.4
20.0
23.1
28.4
36.6
44.8
1
/ For duration of test, see 4.
MIL-STD-883F
METHOD 2026
25 August 1983
4
FIGURE 2026-2. Test condition II, random vibration test-curve envelope (see table II)
.
TABLE II. Values for test condition II
. 1/
Characteristics
Test
condition
letter
Power
spectral
density
Overall
rms G
A
B
C
D
E
F
G
H
J
K
.02
.04
.06
.1
.2
.3
.4
.6
1.0
1.5
5.9
8.3
10.2
13.2
18.7
22.8
26.4
32.3
41.7
51.1
1
/ For duration of test, see 4.