In the open market for electronic components, availability and uncertainty often arrive together. Secondary channels can help recover an end-of-life IC, fill a prototype shortage, or complete a small production lot, but a listing does not establish identity, condition, storage history, or electrical performance. A datasheet defines how a genuine device is intended to behave; it does not prove that the devices in front of a buyer are genuine, unused, correctly stored, or from one homogeneous lot. Quality control therefore begins before the purchase order and continues through evidence review, incoming inspection, risk-based testing, acceptance, and controlled release.

No single inspection proves authenticity. A defensible conclusion combines source context, lot-specific documentation, external and internal consistency, appropriate testing, chain of custody, and written acceptance criteria.

Stage zero: define the requirement and risk

Before requesting photographs or laboratory work, define the exact manufacturer part number, package, speed or temperature grade, revision, date-code rule, quantity, application, and failure consequence. State whether factory-sealed packaging is mandatory, whether mixed lots are acceptable, and whether samples may be consumed. A prototype controller and a field-repair component for safety-related equipment do not justify the same sampling plan. Neither does a low-cost logic gate and a high-value obsolete processor.

Risk input	Examples	Possible response
Low uncertainty / low consequence	Recent traceable lot, standard packaging, noncritical prototype use	Document review, incoming packaging and visual inspection, basic electrical or functional confirmation as agreed.
Moderate uncertainty	Older date code, partial traceability, mixed packaging, scarce small batch	Expanded sample, high-magnification visual and dimensional checks, marking review, solderability or electrical testing where relevant.
High uncertainty / high consequence	EOL device, high value, prior counterfeiting concern, safety or field-failure exposure	Mutually selected independent laboratory; risk-appropriate X-ray, surface analysis, decapsulation or electrical test plan with written criteria.

This table is a planning framework, not a certification claim. The buyer and supplier should choose methods based on the part, source history, package, application, quantity, and defect modes of concern. If a contract invokes a standard such as SAE AS6171, its applicable general and slash-sheet requirements should be handled by a qualified laboratory and stated in the order.

Stage one: documents and packaging

Evidence should describe the actual offered lot. Review manufacturer labels, distributor labels, purchase records where available, packing lists, photographs, quantities, date codes, lot codes, country-of-origin presentation, moisture-sensitivity markings, and package format. Cross-check spelling, typography, barcode content, label construction, and the relationship between inner and outer packaging. A certificate from another shipment or a generic product image does not authenticate the lot being sold.

For moisture-sensitive surface-mount devices, inspect the moisture-barrier bag, seal condition, desiccant, humidity indicator card, and moisture-sensitivity label when those items are expected. IPC/JEDEC J-STD-033 addresses packaging and handling of moisture-sensitive nonhermetic surface-mount devices, including concepts such as MBB, HIC, MSL, floor life, dry packing, and incoming bag inspection. A damaged bag does not automatically mean a counterfeit device, but it can change the storage and bake decision and must be recorded rather than concealed.

Stage two: high-magnification visual inspection

Visual inspection begins at low magnification to understand lot consistency, then moves to a high-magnification optical microscope for the package surfaces, markings, leads, balls, lands, mold features, orientation marks, and edges. Lighting angle matters. Oblique light can reveal sanding patterns, coating boundaries, residue, texture changes, and rework that flat illumination misses. The inspector should compare units within the lot and, when available, with documented known-good exemplars of the same package and assembly site.

Surface and marking review

Look for directional abrasion, an unnatural or uneven coating, filled cavities, inconsistent pin-one indicators, laser marks that cut differently across a resurfaced area, character alignment anomalies, and lot markings that conflict with known manufacturer formats. Chemical surface tests or marking permanency methods may be considered by a qualified laboratory, but results require expert interpretation. Some genuine packages vary by assembly site or manufacturing change, so cosmetic difference alone cannot support a final rejection.

Leads, contacts and solder balls

For QFP, SOIC, SOP, and similar leaded packages, inspect lead coplanarity, bending, scratches, plating consistency, oxidation, contamination, solder residue, and evidence of prior forming or attachment. Oxidation can threaten solderability even when the die is genuine. If the order requires unused material, prior solder evidence is also a condition issue. For BGA devices, inspect ball diameter, spacing, roundness, coplanarity, color, flux residue, and substrate condition. Reball indicators should trigger escalation, but a visual observation must be documented and, where necessary, supported with additional testing.

Stage three: dimensions and nondestructive diagnostics

Measure body length, width, thickness, lead pitch, stand-off, and other package features against the current manufacturer drawing and agreed tolerances. Use calibrated equipment appropriate to the measurement. Weight comparison can sometimes support a broader investigation, but it is not a universal authenticity test and should not replace package or internal analysis.

X-ray is a nondestructive method used to assess internal construction. SAE AS6171/5 describes radiological inspection methods for suspect or counterfeit EEE parts and notes that radiography can compare die attach, bond-wire pattern, leadframe, or other internal construction with an exemplar or within a homogeneous sample population. It can reveal inconsistent die size, missing or irregular bond wires, unexpected leadframes, voiding, damage associated with board removal, or mixed internal populations. X-ray does not identify firmware, prove all electrical functions, or automatically establish provenance. Image setup, sample orientation, resolution, and reference quality affect the conclusion.

Stage four: destructive and electrical options

Decapsulation removes package material to expose the die and internal assembly. A qualified laboratory can inspect die markings, manufacturer logos, mask identifiers, bond pads, bond wires, die attach, and construction. It is destructive and consumes selected samples. Before approval, define sample count, selection method, expected die identification, imaging requirements, who owns the consumed samples, and what result constitutes a pass, reject, or inconclusive finding. A die logo can support identity, but the entire result must be interpreted with package and lot evidence.

Electrical testing should be designed around the risk and available equipment. Options range from continuity, leakage, power consumption, ID-code or memory checks, and key parametric measurements to full functional test on an approved fixture. For programmable parts, document firmware state and security restrictions. For analog parts, define supply, temperature, load, frequency, accuracy, and limits. A brief power-on test cannot be described as full datasheet testing. Conversely, full characterization may be impractical for a small lot unless the application consequence justifies it.

Stage five: chain of custody and decision records

The relationship between the tested sample and delivered balance must remain clear. Assign a lot identifier, photograph seals, record sample selection, document every transfer, and segregate accepted, rejected, and untested quantities. After testing, reconcile consumed and returned samples. Reports should identify the exact part, lot, quantity, methods, equipment or laboratory, results, anomalies, and limitations. If an external laboratory is needed, it should be mutually selected for the RFQ; no standing affiliation is implied by this process description.

Acceptance criteria belong in writing before testing. Define whether one anomaly rejects the lot, triggers expanded sampling, or requires engineering review. Define responsibility for testing cost, destructive samples, return freight, and disposition. A binary “pass” without limits can hide uncertainty. A useful report makes the remaining uncertainty visible so procurement, engineering, and quality can decide together.

What our process promises—and what it does not

Our operating goal is to qualify the evidence and checks available for the specific lot and to align them with the customer's application risk. We can record an agreed new-and-original requirement, review lot-specific information, perform or arrange the agreed inspections, and preserve the resulting decision trail. We do not claim that every lot automatically receives X-ray or decapsulation, that visual inspection alone guarantees authenticity, or that a generic badge replaces testing. The quotation must state the actual scope.

Whether the order is fifty legacy processors, a tray of STM32 microcontrollers, or a small reel of an obsolete interface IC, the same discipline applies: define the requirement, inspect the actual lot, escalate according to risk, agree on independent diagnostics when needed, and release only against documented acceptance. That approach does not eliminate uncertainty from the open market, but it turns hidden assumptions into evidence, test choices, and accountable decisions that protect PCBA yield and field reliability.