Obsolete Electronic Components Testing

The main problems encountered in implementing the activities necessary for the purpose are the following:

1) Reliability of the test houses we address

2) Availability of the same to carry out the tests as, many times, they do not have the software to be able to carry out the tests

3) Quantity and cost of the parts to be tested. Very often the quantities are very low and / or the parts are of low cost, so to carry out the test the costs far exceed the cost of the components.

Given the above, I will list all the activities that can be implemented, starting with those that, in my opinion, are the most important to prevent the aforementioned problems:

1) Counterfeited test:

A) Visual & mechanical:

- Marking resistance to solvent test (mark permanency)

- Datasheet verification: part number marking convention to both prefix & suffix

- Mechanical dimensions

- Package verification

- Leads configuration: leads co-planarity (if applicable) and configuration to datasheet

B) Electrical gross fails testing only:

- Testing includes continuity test, open & shorts test, current test and i / o leakage testing only

- Functional test from known good part learned-mode

C) Del-lid: die marking verification (1 unit from a single date code lot) destructive test. We will supply the photo for all tested parts (not applicable to discrete semiconductors, diodes and transistors, since the die don't show the part number and manufacturer)

D) X-ray per applicable mil-spec-method 2 views (not needed if done test at point "c" which is much more reliable)

2) Testing for microcircuits (IC's)

A) Group A electrical test per device data sheet @ mil-temps (-55, +25, +125c) (for military components)

B) Group A electrical test per device data sheet @ operating temps (for all other commercial, industrial and automotive)

C) DC electrical test for device datasheet @ + 25c (ambient temp)

D) DC & functional test for device datasheet @ + 25c (ambient temp)

E) AC-DC & functional test industrial temps (-40, +25, + 85c)

F) AC-DC & functional test per device datasheet @ + 25c (ambient temp)

G) Memory: EPROM, EEPROM, flash, microcontroller

- Verify blank state (erase if required or possible)

- Load pattern file into programmer buffer & verify checksum

- Program devices and verify at both Vcc low and Vcc high

- Erase devices and perform blank test

3) Testing for discrete components (diodes & transistors)

Group a for MIL-PRF-19500 / sheet dc tests

- Subgroup-1: visual & mechanical inspection

- Subgroup-2: ta = + 25c

- Subgroup-3: ta = hot & cold

Note: all the above tests can also be chosen individually by the customer, for example: in the counterfeited test you can also choose a single test a, b, cod

In addition to the above, where I have exposed the basic tests to have some peace of mind that the parts are good, you can carry out further tests that I list:

4) Environmental & mechanical tests:

A) Constant acceleration

B) Mechanical shock

C) Vibration & shock

D) Thermal shock

E) Hermeticity (fine & gross leak)

F) Moisture resistance

G) Salt atmosphere

The first 4, a, b, c and d, are essential especially if the parts are used in systems that work in extreme conditions (avionics, missile) while the last 3 if the parts are used in mainly marine environments (naval or in bases in environments very humid or near the sea)

Furthermore, the test houses are able to offer a further series of services that could be of interest to the various customers in cases where there are no parts according to the standards required by the customer, for example: component required mil-std-883 class- b, mil component found but not 883 class-b, or JANTX transistor, commercial found:

5) Screening service s for IC's:

A) MIL-STD-883 method 5004 class-b

B) QCI MIL-STD-883 method-5005 class-b

C) Group-A

D) Group-B

E) Group-C

F) Group-D

G) Military temps screening –55 + 125c

H) Automotive temps screening –40 + 100c

I) Industrial temps screening –40 + 85c

6) Screening services for diodes & transistors, TX-screening & qualification JAN & JANTX:

A) TX-screening for MIL-PRF-19500

B) QCI MIL-PRF-19500

C) Group-a

D) Group-b

E) Group-c

7) Resistor, capacitor, inductor, relay, connector and filter:

A) Dc parametric test

B) Ac / dynamic parametric test

C) DWV-dielectric withstanding voltage

D) Insulation resistance

E) Contact resistance

Other types of tests or screening, other than those indicated above, may be taken into consideration on a case-by-case basis and according to the capabilities of the qualified test-houses.

Of course, all these tests have a cost and the more selective they are, the more they cost, therefore, as already mentioned above, we risk being out of the market even if, I agree, that in these cases, we have to give the cost of the component. and apart from the costs of the various tests.

At this point the customer will decide which tests he wants, it depends on the use he has to make of it, for example: it is useless to test a part with environmental tests, if it is then used in an environment that does not undergo vibrations or accelerations of any kind.

Furthermore, all tests must be requested when ordering and cannot be modified later so if the customer is not satisfied with the required tests, he will not be able to dispute a problem related to the tests if not selected before but will have to pay off. the test, complete with the tests that he had not requested when ordering

See Sample Test Plans Index