Analog parts are the most profitable thing to re-mark, because the cheap part and the expensive part come in the same plastic package and mostly work in the same socket. A generic op-amp or reference will power up in place of a precision grade; what changes is offset voltage, drift and gain-bandwidth, which shows up as calibration error or field failure rather than a dead board. Screening a TI or ADI spot lot therefore leans on physical evidence — the acetone wipe that removes a re-marked top layer, the mold dimple and lead finish under the stereomicroscope, and the device identity resolved against the manufacturer's own marking lookup — rather than on the seller's description of the grade.
Table of Contents (8 points)
Why analog and power ICs are the first thing re-marked
A re-marked digital part usually fails loudly and early: it will not program, or it will not boot, and the buyer finds out before the board goes into volume. Analog parts fail quietly. A commercial-grade op-amp sitting in the socket of a precision part will switch on and produce readings that are merely wrong — larger input offset, worse drift, less loop gain — so the defect survives incoming inspection and surfaces as a calibration problem downstream.
The economics push the same way. Two parts in identical SOIC-8 or SOT-23-5 packages can differ by an order of magnitude in price purely on grade, and a re-marker only has to change the top marking to capture that difference. Package and pinout identical, silicon different, and usually nothing in the shipment that says so.
Reading the marking on TI and ADI parts
| Manufacturer | What the marking carries | What to check |
|---|---|---|
| Texas Instruments (SOIC, TSSOP, larger packages) | Device number on the first line, a short letter-and-digit trace string on the second | The trace string is a proprietary lot code, not a format you can decode from a published key. Resolve the device against TI's own part-marking lookup and check that the returned date and lot agree with the reel label |
| Texas Instruments (SOT-23, SC-70 and other small packages) | A 2–5 character top code rather than the full device number | The top code is assigned per device by TI. It has to match the device in TI's lookup exactly; a plausible-looking code on the wrong device is the finding |
| Analog Devices (SOIC, MSOP) | Device root on one line, grade and date information on the next | ADI marking is laser-cut with a consistent typeface and a uniform shallow depth. Re-marked parts show ragged character edges, uneven depth, or a typeface that is close but not the same |
| Linear Technology (now part of ADI) | LTC part number with the LT logo | Cross-check the logo era against the date code. A pre-merger logo on a post-merger date code is a mismatch, and one of the two is false |
What the physical screening actually looks for
- 01 Acetone wipe over the full marking surface. On a genuine part the marking is cut into the package and the swab comes away clean. On a re-marked part the black topcoat begins to smear off, taking the fake part number with it and exposing what was under it — often the ghost of the original marking or visible sanding.
- 02 Pin-1 dimple and mold tooling at 45x. The index dimple and mold ejection marks hold the original matte mold texture on a genuine part. Where a topcoat has been sprayed over the package, resin pools in those recesses and dries glossy, or fills them part-way.
- 03 Lead finish and package edge. Genuine parts show uniform matte tin or the specified plating over a clean leadframe. Salvaged and re-tinned parts show solder bridging at the package meniscus, thinning at the lead tips, or tarnishing where the original finish was stripped.
- 04 Device identity from the marking. The top code or device number is resolved through the manufacturer's own marking lookup and compared with the reel label. This is the one check that can prove what the device is, rather than only that it is suspicious — which is why an unresolvable code is treated as a failure, not a formatting quirk.
Grade claims are the part of the description we do not take on trust
Sellers describe grade in words — precision, low-offset, automotive. Those words are the entire value of the part, and they are also the entire content of the re-mark. So the grade is never carried over from the quote into what we ship: the lot is identified from the marking and the reel label, the physical checks above are run on the actual material, and the buyer sees the photographs of the parts they are paying for before the invoice is settled.
Where a buyer needs a defined grade, we would rather name the exact orderable part number than accept a description. A precision op-amp sourced as AD8605ARTZ-REEL7, a reference as REF5025AIDGKR, a comparator-grade part as LM311DR — the orderable number is checkable; "precision grade" is not.
Parts named in this guide
CatalogEach of these is a part or part family this guide covers, linked to the catalog row we hold for it — specifications, package, lifecycle stage and the datasheet where we have localized one. Where the guide names a family, the row shown is the orderable part number we stock. A part the guide covers but that is missing from this list is one we do not currently carry; send the number and it goes out for sourcing with the rest.
| Part number | Manufacturer | Description |
|---|---|---|
| AD8605ARTZ-REEL7Datasheet | Analog Devices | IC OPAMP GP 1 CIRCUIT SOT23-5 |
| REF5025AIDGKR | Texas Instruments | IC VREF SERIES 0.1% 8VSSOP |
| LM324DRDatasheet | Rohm Semiconductor | IC OPAMP GP 4 CIRCUIT 14SOIC |
| TL431AIDBZRDatasheet | Texas Instruments | Texas Instruments TL431AIDBZR, adjustable shunt voltage reference, ±1% tolerance, 2.495 V min output, 100 mA cathode current, SOT-23-3 surface-mount package, -40°C to 85°C. |
| TPS54302DDCRDatasheet | Texas Instruments | Texas Instruments TPS54302DDCR, Step-Down Buck Regulator, 3 A Output, 4.5 V to 28 V Input, 400 kHz Switching, Adjustable Output, SOT-23-6, -40°C to 125°C. |
| LM311DRDatasheet | Texas Instruments | Texas Instruments LM311DR differential comparator, General Purpose type, MOS/Open-Collector/Open-Emitter/TTL output, 8-SOIC (0.154", 3.90mm Width) surface-mount package, Tape & Reel. |
Put this to work on your component list
Send the part numbers or the whole BOM sheet. Each line comes back with current spot availability, original manufacturer condition, and verified cross-references — packed and shipped together in one single parcel.
Standards & documents referenced
How this guide is written
Written by the ICBOMS sourcing desk in Shenzhen and reviewed against the manufacturer documents and industry standards the guide cites. Statements are limited to what this desk does and how a part is judged — no indicative prices, lead times or stock counts, because those are quoted per line against a live check. Each guide carries the date it was last reviewed at the top of the page.