Group A Electrical Testing

Group A testing is industry terminology for testing the component device’s full functional and parametric require-ments at the recommended manufacturer’s or specific industry extreme operating temperatures as presented in this table.

Industry Temperatures Test Objectives
Commercial 0°C – 70°C DC, AC Functional and Parametric Testing
Industrial -40°C – +85°C DC, AC Functional and Parametric Testing
Automotive -45°C – +110°C DC, AC Functional and Parametric Testing
Military / Aerospace -55°C – +125°C Subgroups 1, 2, 3, 4, 5, 6, 7, 8A, 8B. 9, 10, 11
Space -65°C – +150°C Subgroups 1, 2, 3, 4, 5, 6, 7, 8A, 8B. 9, 10, 11

The test objectives are to exercise the DC and AC functional and parametric requirements as indicated on the in-dustry specifications. In cases of military, aerospace, and space design, the respective subgroups contained in those documents would suffice for the objective tests.

Radiographic Inspection and Internal Visual Verification

Radiographic Inspection
After checking the Physical Dimensions, Real-time X-ray and shadowgraph X-rays are performed to observe evidence of counterfeiting by analyzing the die size and wire bonding and to uncover any possible delaminations.
Internal Visual Verification
Component samples are delidded, and an internal inspection is made. The die is checked for defects, and the manufacturer’s logo on the die must match that on the lid of the component. The die topography also is analyzed to see if it meets the outline of the manufacturer’s requirements.
The component is placed under a high-powered microscope and verified against the manufacturer’s specifications. Photographs of this process are taken each step of the way. In the event of insufficient verification data, engineer-ing consultation will refer to other methodologies in the process to uncover counterfeit or cloned devices.

Physical Dimensions and Marking Permanency

Over the past few years, NJMET’s testing has encountered new techniques of blacktop marking that could easily pass the MIL Handbook resistance to solvents criteria. We have researched methods to test for these new techniques as well.

Physical Dimensions
The height, length, width, and depth as well as arc angle, curvature measure, and pin-count of the devices are checked. This ensures all data meets the manufacturer’s specification and that there is no evidence that the components have been altered.
Marking Permanency
The purpose of this test is to verify that the markings will not become illegible on the component parts when subjected to solvents. (See picture.) Various military standard procedures are used that incorporate several chemicals mixed appropriately and in detail in accordance with the specifications. These chemicals consist of aliphatic alcohol, mineral spirits, ethyl-benzene, organic solvents, deionized water, propylene glycol monomethyl ether, or monoethanolamine.

Once the chemicals are mixed, the components are submerged in a three-phase process and analyzed in accordance with MIL-HBK-130 to uncover evidence of damage to the device and any specified markings. The analysis includes missing markings in whole or in part or those that appear, faded, smeared, blurred, or shifted to the extent that they cannot be readily identified from a distance of at least 6 inches with normal room lighting and without the aid of magnification.

NJMET: Mission Imposter electronic component with suspect markings
NJMET's Mission Imposter testing finds components with suspect markings.

In some cases, a strategic acetone wash is used to reveal sanding marks and facets of previous markings. Over the past few years, new techniques of blacktop marking have been discovered that could easily pass the MIL Handbook resistance to solvents criteria.  We have researched methods to test for these new techniques as well.

ESD: Electrostatic Discharge Surface Inspection

Because Electro-Static Discharge is one of the most serious problems facing the electronics industry today, a trained staff of operators thoroughly examine the electronic components and packaging to detect evidence of plastic, styrofoam, rubber bands, cardboard, scotch tape or any substance capable of inducing static electricity to the product. These particular items can cause the “shock” you sometimes feel in the winter when you walk across a carpet and touch a doorknob, or the “crackling” sound you hear when you remove clothes from your dryer. Although ESD may seem harmless, it can damage electronic components and their assemblies when not packaged or handled properly.

Incoming Inspection

The inspection process starts with checking the boxes for shipping damage or evidence of a counterfeit or suspect barcode label and moves on to the component level after the packages are opened. An in-depth, near 100-point inspection process via a detailed checklist of suspect error types and optical microscopy (digital imaging) is performed to verify the component part number, marking, lead straightness, color, or any anomaly related to the integrity of the devices such as cracks, dents, scratches, mechanical anomalies, spelling errors, suspect date codes, suspect manufacturers’ logos, breaks, or corrosions.

Counterfeit Electronic Components

Imposters seem to be creeping into all facets of our life: fake IDs, knock-off designer handbags, and now even into our electronic components supply. Thanks to a program originated at NJMET, the imitation electronic devices that began infiltrating the industry close to a decade ago now can be detected.

NJMET created Mission Imposter®, the first program that detects counterfeit electronics before they find their way into customers’ products. The process begins with analyzing the shipping and packaging. It continues with the parts undergoing several levels of inspection including marking and dimensional checks, internal visual analysis, several levels of material analysis, and electrical testing to determine as well as ensure authenticity. In total, there are 15 options in this process to uncover counterfeit or cloned devices.
Over the next several posts, I will briefly explain each of these procedures. In the meantime, if you want to know more, check out the Mission Imposter pages on the NJMET website: