YURUNOX · Semiconductor identity and traceability
Why the Same MPN Has Different Markings
The same manufacturer part number can legitimately carry different package markings. The MPN identifies the orderable product, while the body can also show changing date, lot, wafer, assembly-site, test-site, revision, environmental, or 2D trace data. Accept the difference only when the fixed identity, package, labels, official marking rules, PCN history, and approved source all reconcile.
The answer in one minute
Two genuine parts with the same complete MPN can look different because the package is doing two jobs. It carries a stable product identifier and variable genealogy. A new production week changes the date code. A new lot changes the trace code. A qualified assembly site can add a different site code. A controlled silicon revision can change a version field. A manufacturer may also move a logo, add a line, change the laser layout, or introduce a 2D Data Matrix under a formal notification.
Usually normal
Documented date, lot, wafer, assembly, or test-trace fields differ while the fixed device code, package, label, source, and approved history agree.
Needs review
A PCN explains a new site, material set, die revision, logo, marking method, or 2D layout, but the project has not dispositioned it.
Quarantine first
The fixed code, package, grade, label, or date conflicts; no official record explains the difference; or the source and repack history are inadequate.
Technical examples below were checked against current TI, NXP, Analog Devices, and Infineon manufacturer records. Review date: 28 August 2026.
Separate fixed identity from variable trace data
A top mark is not necessarily a second copy of the purchasing MPN. Space is limited, especially on QFN, WLCSP, µSOP, and other small packages. The manufacturer may print a shortened device or family code on top and keep the complete orderable string, carrier, quantity, and barcode data on the reel, tray, bag, or box label.
Illustrative marking anatomy · not a universal decoder
Fixed product field
Expected to map to the exact device/package or a manufacturer-approved marking change.
Variable genealogy
Date, lot, wafer, site, revision, environmental, or individual trace data can change.
The real layout is product-specific.
Use the exact datasheet, marking lookup, or manufacturer support record.
| Record | Fixed or variable? | Its real job |
|---|---|---|
| Complete manufacturer MPN | Normally fixed for the ordered item | Defines the commercial and BOM identity, including package, grade, or carrier fields where encoded. |
| Device/family code on body | Usually fixed; can change under a marking PCN | Maps the physical package to a manufacturer marking diagram. |
| Date or work-week field | Variable | Identifies manufacturing or assembly time under that manufacturer’s format. |
| Lot, wafer, assembly, or test trace | Variable | Links the device to internal manufacturing genealogy. |
| Die, mask-set, or hardware revision | Can change during product life | Distinguishes a controlled silicon or backend version that may affect errata and validation. |
| Environmental/process symbol | Scheme-dependent | Indicates a documented lead-free, wire-material, or environmental category; it is not the full compliance record. |
| Manufacturer shipping label | Variable by shipment; includes fixed MPN | Bridges the full order code, quantity, lot, carrier, and trace information to the packed material. |
Eight legitimate reasons the same MPN looks different
| Visible difference | Why it can happen | Required check |
|---|---|---|
| 1. Date code | Production time changed. Formats may use year/month, year/week, Julian day, or compressed codes. | Use the exact manufacturer legend; test whether the implied date is plausible for the product and shipment. |
| 2. Lot or wafer trace | Each manufacturing lot needs distinct genealogy. Identical trace characters across every lot would defeat that purpose. | Preserve original labels and group material by the complete observed trace. |
| 3. Assembly/test site | More than one qualified factory or subcontractor can build/test the same MPN. | Confirm the site code, PCN, effective date, materials, qualification, and any customer approval requirement. |
| 4. Extra line or 2D code | The manufacturer improved internal traceability or changed marking equipment/layout. | Find the marking PCN/CIN and update controlled visual references for both eras. |
| 5. Die or mask revision | A qualified silicon version changed while the sales MPN remained in use. | Review PCN, errata, firmware workaround, safety analysis, validation, and mixing rules. |
| 6. Line breaks/abbreviation | Package area or manufacturer layout rules require a shortened device code or split lines. | Match the exact package-specific diagram; retain uncropped photos with spaces and punctuation. |
| 7. Environmental/process symbol | Lead-free, backend, wire-material, or environmental indicators may appear or move. | Verify the exact MPN’s compliance and material documents; do not rely on the symbol alone. |
| 8. Data kept on the label | Carrier, full suffix, quantity, country, and barcode data may not fit on the body. | Reconcile device, reel/tray/bag label, outer box, PO, and any controlled repack label. |
The format is never universal. A one-digit year code can repeat each decade, and an internal lot code may not be publicly decodable.
A date code is not an age-quality score
A date field helps group material and test chronology. It does not by itself state remaining life, storage history, moisture exposure, authenticity, or electrical quality. Those questions need packaging condition, MSL controls, chain of custody, and risk-based inspection.
Set date-code limits only when there is a justified engineering, regulatory, customer, or process reason. Arbitrary “newer is always better” rules can reject correctly stored, fully conforming material without addressing the actual risk.
Three documented cases—and three different decisions
These are public manufacturer change records, not YURUNOX shipment claims. They show why the type of changed field matters more than the visual size of the difference.
NXP PCN 201904029F01 · assembly-site transfer
Trace prefix changed from ZR to XN
NXP transferred listed MC9S08SH4/SH8 PDIP20 parts from ATP1 in the Philippines to TFME in China. The notice states that the package trace format includes assembly location, wafer lot, date code, and assembly-lot split; the old assembly identifier was ZR and the new one XN. The PCN also documents changes in mold compound, wire metal, and lead frame, while stating no impact on form, fit, function, reliability, or quality.
Decision: do not reject the new prefix as a wrong MPN, but do not reduce the event to “font variation.” Review the exact affected MPN list, materials, effective date, qualification, and any customer flow-down before approving inventory mixing.
NXP CIN 201710043I and CIN 202007041I · trace layout
A fifth line and a 2D Data Matrix appeared without creating new products
For SAF7741/SAF7740, NXP announced an additional unique device ID on a previously unused fifth line to improve internal traceability. For selected FXTH87 products, NXP added a 2D Data Matrix, moved the logo, and replaced visible part-number text with a family code while retaining the trace code. Both notices describe marking changes with no stated impact on form, fit, function, reliability, or quality.
Decision: replace the “one golden photo forever” rule with a controlled marking specification that includes old and new approved layouts, PCN number, affected MPNs, and effective date.
NXP PCN 201907014F01 · silicon revision
Marked version changed from 0A to 1B under affected sales MPNs
NXP changed LPC55S66JBD100 and LPC55S69JBD100 products from version 0A to 1B. The version is recognizable in the product marking, and the revised silicon resolves a list of errata. NXP states no impact on form, fit, function, reliability, or quality, yet firmware workarounds and a project’s validated configuration can still refer to a particular revision.
Decision: route a die/mask revision to engineering and quality. Review the PCN and errata, decide whether workarounds or validation change, define allowed mixing, and then update the AVL and incoming criteria.
Primary records: NXP 201904029F01, 201710043I, 202007041I, and 201907014F01.
Manufacturer examples show why generic decoders fail
Texas Instruments: device mark and lot trace are different fields
TI’s quality FAQ defines the Lot Trace Code as a seven-digit code marked on a device for one lot processed through a controlled assembly flow; it can appear on one or two lines. TI’s exact TPS5430 marking lookup separately identifies the device name, year/month assembled, lot trace, secondary code, pin-one stripe, and an optional environmental category. It also warns that small packages may abbreviate the lot trace.
Sources: TI quality, reliability and packaging FAQs; TPS5430DDARG4 top-side marking legend; TI part-marking lookup.
Analog Devices: stable visible product lines can coexist with changing underside data
ADI’s support record for MAX5235AEUB+ gives stable top lines and explains that underside markings indicate date, lot, assembly site, and other manufacturing information that “can and do change.” Its DS1804 guide demonstrates package-specific marking because different bodies have different available space, with fields for assembly year/week, die revision, lot digits, suffix, and assembly country.
Sources: MAX5235AEUB+ top-marking guidance; DS1804 ordering and package-marking guide.
NXP and Infineon: a body can omit the orderable extension or add process indicators
The current NXP MCX N datasheet describes top-side markings where the visible part number can omit package-extension information, while other lines carry lot information, year/work week, and mask set. Infineon’s published Cypress marking format includes examples with marketing part number, date code, backend revision, fab site, lot code, a lead-free mark, and—where applicable—a C indicator for copper wire.
Sources: NXP MCXN947/946/547/546/537/536/527/526/247 datasheet; Infineon/Cypress marking format.
Use four evidence layers, not one photograph
- Commercial identity.Start with approved manufacturer name and complete MPN from the BOM and PO. Separate it from distributor SKU, internal item number, customer drawing, and carrier description.
- Physical identity.Confirm package family, dimensions, pin/ball count, pitch, pin-one indicator, exposed pad or ball field, and fixed product code against the exact datasheet or marking lookup.
- Manufacturing genealogy.Read date, lot, wafer, site, test, revision, and 2D fields as changing trace data. Preserve exact photographs and keep distinct mark/label groups separated.
- Change and source evidence.Check PCNs, errata, qualification, original labels, shipping records, chain of custody, repack history, and supplier response. A valid PCN explains a possible change; it does not prove the received lot followed the claimed chain.
| Evidence | What it can establish | What it cannot establish alone |
|---|---|---|
| Datasheet/marking diagram | Expected fixed and variable field positions for a documented product/package | Current source legitimacy, storage, or lot genealogy |
| Manufacturer PCN/CIN | Approved marking, site, material, process, or revision change and affected MPNs | That received material actually came through the claimed channel |
| Original manufacturer label | Complete MPN, lot, quantity, carrier, and shipment trace data | That contents were never swapped after the label was created |
| Package marking | Physical device code and manufacturing-trace clues | Complete MPN, authenticity, or electrical conformity by itself |
| Authorized-chain records | Strong transaction and chain-of-custody evidence | Freedom from handling or receiving error; physical reconciliation remains necessary |
| Electrical/lab inspection | Measured behavior or construction within the test scope | Full genealogy, unused condition, or every hidden defect |
Escalated testing must answer a defined risk
Visual inspection can document mark quality, surface condition, package dimensions, and group differences. X-ray, XRF, decapsulation, microscopy, and electrical tests answer different questions and can be destructive or sampling-limited. A qualified plan should state the suspected failure mode, sample basis, reference device, acceptance criteria, and limits of the conclusion.
Do not call a lot authentic because one test passed, or counterfeit because one photo looks unusual. Record what the evidence establishes and what remains unresolved.
When to accept, review, or quarantine
Normal process
Accept
The fixed product code and package match; only documented variable fields differ; labels reconcile; date/lot data is coherent; the source policy is met; and relevant PCNs/revisions are already approved.
Controlled hold
Review
A PCN explains a new site, material, die revision, logo, laser method, or 2D format, but engineering, quality, PPAP, safety, or customer approval has not been completed.
Preserve evidence
Quarantine
The fixed code, package, grade, label, suffix, date, or source conflicts; exact PCN coverage is missing; the lot is undisclosed/mixed; or alteration, resurfacing, relabeling, or uncontrolled repacking is suspected.
Four illustrative scenarios
- New assembly code with exact PCN coverage: verify effective date and label coherence, complete customer/quality review, then approve or reject the manufacturing change.
- New 2D code rejected by an old golden photo: locate the marking notification and update the controlled visual standard to include both authorized eras.
- New mask revision on the same sales MPN: review errata and firmware/validation impact before lot mixing.
- Professional-looking cut-tape label but unexplained fixed code: quarantine until the body mark, original label, source chain, and manufacturer record reconcile.
These scenarios are illustrative decision models, not reported customers, shipments, test results, or authenticity findings.
Marking-difference triage aid
This aid organizes the next action. It does not authenticate a component, replace a manufacturer response, or release quarantined material.
Proceed through normal lot controls
- Record each date/lot group and retain label photographs.
- Confirm the fixed device code and package.
- Release only under the approved source and receiving procedure.
Triage output only. Final disposition belongs to the buyer’s authorized engineering and quality process.
RFQ and incoming-inspection controls
YURUNOX is an independent electronic-component sourcing partner, not the manufacturer of the cited devices and not a legal authenticity authority. Manufacturer documents remain the marking and change-control reference. A useful sourcing review connects those records to the exact offer, source path, packaging, and received lot.
Specify variation before the supplier ships
State whether mixed date codes, mixed lots, multiple assembly sites, or multiple die revisions are acceptable. Ask for original manufacturer packaging and lot-specific label photographs when traceability matters. Define repack and cut-tape rules rather than discovering them at receiving.
A supplier deviation process is more useful than an absolute “all markings must look identical” clause. It gives engineering and quality a controlled way to evaluate documented change without letting unexplained variation enter production.
Minimum RFQ record
- Exact identity.Complete manufacturer MPN, approved suffixes, package, electrical/temperature/quality grade, quantity, and packing format.
- Allowed lot variation.State rules for mixed date codes, lots, assembly/test sites, and die or mask revisions.
- Source and packaging.Define authorized-source or independent-source evidence, original packaging, repack/cut-tape controls, label photos, country data, MSL and dry-pack requirements.
- Change control.Request PCN/PDN notification, revision approval, PPAP/customer approval where applicable, samples, and supplier deviation workflow.
- Response terms.Define hold, investigation, return, warranty, and evidence preservation for unexplained marking or label differences.
At receipt
- Photograph unopened packaging.Capture outer, inner, bag, reel, tray, tube, cut-tape, and repack labels before material is split.
- Reconcile the complete MPN.Compare label, PO, approved BOM/AVL, package, and carrier. Record distributor SKU separately.
- Group before sampling.Separate parts by fixed code, date/lot/site/revision fields, package appearance, and label lot. Do not hide mixed groups in one sample.
- Use exact official records.Check the product/package marking lookup and relevant PCNs with affected MPNs and effective dates.
- Escalate unexplained groups.Quarantine, preserve every evidence layer, and request a written lot-specific response. Test only under an approved risk-based plan.
- Update the controlled range.When a difference is approved, store the decision, evidence, old/new marking layouts, dates, and revision limits so the next lot is judged consistently.
Build a reviewable evidence package
Send the MPN, labels, markings, and lot groups together
Include clear uncropped device and packaging photos, the complete MPN, quantities by mark group, source route, applicable PCNs, and project approval constraints. YURUNOX can structure a sourcing and evidence response around those fields.
- Complete MPN and package
- Outer and inner label photos
- Top/bottom marks by group
- Quantity, date, lot, site, revision
- Source and PCN evidence
See YURUNOX’s quality-assurance approach, purchasing process, and relevant TI, Analog Devices, Infineon, and frequently asked questions pages.
Frequently asked questions
Can two genuine chips with the same MPN have different markings?
Yes. Date, lot, wafer, assembly-site, test-site, revision, environmental, or 2D trace fields can differ, and a manufacturer may change the layout under a PCN. The fixed product identity and package must still reconcile with official documentation and labels.
Does a different date code mean a different part?
No. It normally means a different manufacturing period. Check the exact manufacturer format because year/month and year/week schemes vary, and small packages may abbreviate the code.
Why can the assembly-site code change if the MPN is the same?
Manufacturers may qualify multiple factories or subcontractors for the same product. A trace field identifies the site. Review the applicable PCN, affected MPN, materials, qualification, and customer approval rules before accepting the new site.
Can the die revision change without a new sales MPN?
Yes. A manufacturer may retain the sales MPN while changing a marked die or mask revision. Engineering should review the PCN, errata, firmware, safety analysis, validation, and lot-mixing impact.
Why is the full MPN not printed on the chip?
Package space is limited, and some suffixes describe package or shipping options better represented on the reel or tray label. The chip may use a short device code plus variable trace fields. Use the exact marking diagram to connect it to the complete MPN.
Does a different font or laser appearance mean counterfeit?
Not by itself. Marking equipment, factory, process, logo, or a controlled layout can change appearance. Unexplained differences still require evidence review and possibly qualified inspection, but appearance alone cannot prove authenticity or counterfeiting.
Is a matching reel label enough to accept different markings?
No. The label is important, but it must reconcile with the actual package, fixed product code, lot groups, official marking information, and source chain. Labels can become separated from contents during uncontrolled repacking.
Should incoming inspection require one exact golden marking photo?
Usually no. A single photo becomes obsolete when date, site, revision, logo, or 2D code changes. Maintain a controlled marking specification with fixed fields, allowed variable fields, approved PCNs, effective dates, and escalation rules.
Primary technical sources
- Texas Instruments, Quality, Reliability & Packaging FAQs, part-marking lookup, and TPS5430DDARG4 marking legend.
- NXP Semiconductors, PCNs 201904029F01, 201710043I, 202007041I, and 201907014F01.
- NXP Semiconductors, MCXN947/946/547/546/537/536/527/526/247 Data Sheet.
- Analog Devices, MAX5235AEUB+ top-marking guidance and DS1804 marking clarification.
- Infineon Technologies, Cypress Marking Format.
Marking formats and change histories are product-specific. Recheck the exact datasheet, package, marking lookup, PCN, and received-lot evidence before making a release decision.