onsemi product discontinuance notice PD27509X, issued on 10 July 2026, ends 150 standard part numbers. The last time buy date is 10 January 2027 and the last ship date is 10 July 2027. For 94 of the 150 codes onsemi names no replacement at all, including all 24 FOD2741, FOD2742 and FOD2743 feedback optocouplers and 22 legacy UnitedSiC silicon carbide devices. Once a part is on the notice, orders for it become NCNR (non-cancelable, non-returnable). As of late October 2026, buyers who still have one of these codes on a live BOM have about ten weeks to place the final order.
We read the notice's attached standard-part list (in the copy distributed to EBV Elektronik) line by line and sorted every code by family and replacement type. This post is the triage that results: which codes to deal with first, the replacement that looks safe but is not, and what the final purchase order has to cover.
The four dates in PD27509X, and the one that already passed
PD27509X runs on four dates, and the 90-day sole-source window has already closed for most buyers: anyone who received the notice on 10 July 2026 had until roughly 8 October 2026 to tell onsemi in writing that a part is sole source.
| Date | What happens | What it means for a buyer |
|---|---|---|
| 10 July 2026 | Notice issued (TEM001799 Rev. J) | The clock starts. Affected devices become NCNR. |
| About 8 October 2026 | End of the 90-day sole-source declaration window | After this, a negotiated end-of-life arrangement is no longer covered by the notice terms. |
| 10 January 2027 | Last time buy | The final lifetime order must be placed. onsemi may set minimum order quantities or values based on inventory. |
| 10 July 2027 | Last ship | onsemi plans to deliver nothing after this date, although it may extend it at its discretion. |
Six months to the last order and twelve months to the last shipment is the baseline in the JEDEC J-STD-048 product discontinuance standard, so onsemi is giving the minimum, not extra time. If you missed the sole-source deadline, it is still worth writing to the onsemi Europe contact named in the notice (based in Slovakia). Just do not plan on it working.
Triage: 94 no-replacement codes first, 43 "Similar" second, 13 "Direct" last
Handle the 94 codes with no replacement first, because each one means an engineering change, a lifetime buy or both. The 43 codes marked "Similar" come second, and the 13 "Direct" codes can go through a normal approval. Here is how the 150 codes split by family:
| Family | Codes | No replacement | Similar | Direct |
|---|---|---|---|---|
| UnitedSiC SiC diodes, cascode FETs and modules (UJ3D, UJ3C, UF3C, UHB, UFB) | 35 | 22 | 9 | 4 |
| MB8x/MB9x-prefixed codes, including MB85 FRAM | 30 | 30 | 0 | 0 |
| Power controllers (NCP, SCY, NIS, MC33063 and others) | 26 | 6 | 19 | 1 |
| FOD2741, FOD2742, FOD2743 optocouplers | 24 | 24 | 0 | 0 |
| Other (logic gates, SiPM sensors, image sensors, custom codes) | 17 | 8 | 1 | 8 |
| Power MOSFETs and DrMOS (FDMS, FDMC, FDMT, NTTFS, NTBL, FDMF) | 13 | 4 | 9 | 0 |
| FAN53526 buck regulators | 5 | 0 | 5 | 0 |
| Total | 150 | 94 | 43 | 13 |
Many of the Direct codes are small changes: the logic gate MC74VHC1G32EDFT2G moves to MC74VHC1G32DFT2G and NL17SZ06EDFT2G to NL17SZ06DFT2G, the same package and pinout without the "E" variant. For a non-safety part, a buyer can usually approve a change like that against the datasheet. Before you file anything as Direct, run your own codes against our part number suffix decoder. The 30 MB-prefixed codes are a separate task: none has an onsemi replacement, so qualify a new part or buy for the life of the product.
FOD2741, FOD2742, FOD2743: why 24 optocoupler codes are the hardest line
The FOD274x codes are the hardest part of this notice because no onsemi replacement exists and each part does two jobs. It packs an LED, a phototransistor and a 2.5 V precision shunt reference into one 8-pin package, so it acts as the whole isolated error amplifier in the feedback loop of an off-line switch-mode power supply. Swapping in a standard optocoupler plus a separate TL431-type reference means a new layout, two parts instead of one, and new loop compensation.
Buyers who ask on forums whether a part swap forces new compliance tests usually hear "not usually, unless the part is safety-related". An optocoupler across the isolation barrier is the standard example of a part that is. That applies here directly. In Fairchild-heritage optocoupler codes the V suffix typically marks the VDE safety-approval option (confirm it in the datasheet ordering table). The notice lists 13 of the 24 codes with a V, among them FOD2741BSDV, FOD2741ASV and FOD2743BTV. If your power supply was certified with one of those V parts as the isolating component, a new optocoupler is a certification question for your test house, not a purchasing decision. For a German or EU manufacturer selling CE-marked equipment, that is usually the step that decides the timeline.
The other suffixes matter just as much for the last order. Distributor listings show the S and SD codes as surface-mount versions, with SD supplied on tape and reel, while plain codes such as FOD2741BV are through-hole. Check the exact code on your approved vendor list: a lifetime buy of FOD2741BSD will not fit a board laid out for the through-hole FOD2741B.
UnitedSiC silicon carbide: a "Similar" replacement can change the package
Do not treat "Similar" as safe for the legacy UnitedSiC parts. onsemi's own definition says a Similar replacement may change the pinout or the package, and in this family it does. onsemi took over the UnitedSiC line when it bought Qorvo's silicon carbide JFET business in January 2025. The notice now drops 35 of those codes, 22 of them with no replacement, mostly UJ3D SiC Schottky diodes.
The clearest example is UF3C065030B3, a 650 V, 27 mOhm SiC cascode FET in a D2PAK-3L surface-mount package. Its listed Similar replacement is UF3C065030K3S, the same 650 V, 27 mOhm class in a TO-247-3L through-hole package. On paper the electrical match is close. In practice it means a new footprint, a different thermal path and a different soldering process. The same B3 to K3S move appears for UF3C065040B3, UF3C065080B3 and UJ3C065030B3.
The same package check applies outside silicon carbide. MC33063AVPG, the PDIP-8 version of the long-running buck-boost controller, gets MC33063AVDG as its Similar replacement. That is the SOIC-8 version, so a through-hole board needs a respin or a lifetime buy. If you substitute SiC parts from other manufacturers, check export status too: our post on the 2026 EU dual-use list for SiC and GaN covers the export-control side.
Worked example: sizing the final order for a FOD2741BSDV line
The order must cover every unit you will build after July 2027, plus scrap and service spares, rounded up to full reels. It cannot be cancelled later. Here is the calculation for a German industrial power-supply line that uses one FOD2741BSDV per unit:
- Build rate: 4,000 units a year, with production planned through December 2030. From the January 2027 order date that is 4 years, or 16,000 parts.
- Assembly scrap and test losses at 3%: 480 parts.
- Field repair spares at 2% of the installed base: 320 parts.
- Total: 16,800 parts, rounded up to full reels.
Two checks before signing. First, the redesign route: if a qualified replacement optocoupler can be certified within 18 months, the order only needs to bridge that gap. That might be about 6,000 parts instead of 16,800, which keeps less cash tied up in stock that cannot be returned. Second, storage: four years of optocouplers on a shelf need dry, controlled conditions and date-code tracking, as covered in our guide to shelf life and date codes. If you over-buy, plan from day one to sell the excess rather than writing it off. Our last time buy strategy guide covers the full method.
Ordering early also helps because the wider market is tight. In the Global Electronics Association's August 2026 sentiment survey, 64% of manufacturers said components were only available in limited quantities or with extended lead times, and 53% said supplier lead times had risen in Q2 2026. Final orders that arrive in the first week of January compete with everyone else's.
What we checked in our own onsemi stock
We compared all 150 PD27509X codes against the onsemi part numbers listed in the GlobX catalog. As of October 2026 none of them is on the notice. That includes two codes from the same power-conversion families: the FAN4800CSMY PFC and PWM combination controller (SOP-16, 11,290 pcs in stock, date code 22+) and the FAN5362UMP33X 3 MHz synchronous buck regulator (19,500 pcs, date code 22+). These are not replacements for any PD27509X code. They show that a family appearing on a notice does not mean a given code is affected. Always match the full ordering code, never the base part number.
For codes with no onsemi replacement, the notice names Rochester Electronics and Flip Electronics as the partners that will hold any remaining onsemi inventory after the last ship date. That is a real continuity option, but it gives no price or quantity guarantee. A parametric search is the other route; our cross-reference guide explains how to run one without approving a false match. For how notices like this one are structured, see PCN and EOL notices explained.
Send us your affected codes before Christmas
Send GlobX the full ordering codes from your BOM, your annual usage and the year your product goes out of production. We will tell you which codes are on PD27509X, which Similar replacements change the package, and what lifetime or bridge quantity we can source for the codes with no replacement. Order quantities need to be set before onsemi closes the books on 10 January 2027, so the useful deadline for an RFQ is mid-December. Contact our sourcing team with your list.
