Using a memory-market headline as a purchasing deadline can leave the wrong part on a last-time-buy list. The DDR3 or DDR4 EOL date for your BOM must come from a notice that covers the complete manufacturer part number, with purchase and shipment deadlines recorded separately.
The notices examined here do not establish one industry-wide cutoff. This checklist helps an embedded-system engineer or buyer decide which BOM lines need supplier clarification, a stock plan, or evaluation of a replacement. It does not forecast prices, inventory, or availability for an unlisted part.
Two memory modules and a small circuit board on a beige bench mat.
- Match the full ordering code, including revision and suffixes, to the affected-parts table.
- Keep announcement, last purchase, and last shipment dates in separate fields.
- Treat a recommended replacement as a candidate for review; record your qualification decision separately.
- Leave missing dates blank until the supplier provides a dated answer for that part.
Which date actually belongs in the BOM review?
A product change notification (PCN) can document an end-of-life event, but its publication date alone does not tell you when orders or deliveries stop. Read the notice’s own labels and conditions before translating them into your purchasing system.
| Field | What to record | What it lets you decide |
|---|---|---|
| Announcement or release date | Date printed on the notice, plus its identifier and revision | Which document you reviewed |
| Last purchase date (LPD) or last-time-buy date (LTB) | Exact date and ordering conditions in that notice | When a purchase decision needs to be resolved |
| Last shipment date (LSD) or last-time-ship date (LTS) | Exact date and any written exception | Whether the documented shipment window fits the build plan |
| Sample availability | Wording and date in the notice | Whether to ask about evaluation material; it is not an order deadline |
| Replacement and qualification | Proposed ordering code, supporting documents, and your approval status | Whether a replacement is ready for your approved BOM |
The label mapping above is a reading aid, not a universal supplier contract. Micron’s example below uses LPD and LSD; Alliance’s uses LTB and LTS. Preserve the original wording next to the normalized field.
What do the actual DDR3 and DDR4 notices show?
These are bounded document examples, not a complete EOL list or a statement that an old notice is the latest notice for your product. Check for superseding documents before acting.
Micron PCN 34165: a historical example with separate deadlines
Micron’s PCN 34165, published June 2, 2021, discontinues select DDR3, DDR4 and RLDRAM components and modules. Its affected-parts list includes MT41J256M8DA-125:K and MT40A2G4SA-062E:J. Page 2 gives a last purchase date of December 2, 2021 and a last shipment date of June 2, 2022. Those dates apply to the notice’s listed products, not every DDR3 or DDR4 device.
For MT40A2G4SA-062E:J, the table recommends MT40A2G4SA-062E:R; for MT41J256M8DA-125:K, it directs the reader to a sales representative. Do not invent an alternative for the latter row. The notice also discusses non-cancelable, non-returnable orders and written approval for changes to confirmed request dates. Read those conditions with purchasing before treating a date as an unconditional supply commitment. Read Micron PCN 34165.
Apacer PCN 202603310001: release date present, order deadlines absent
Apacer’s one-page notice, released March 31, 2026, identifies affected module 78.D1G3F.AT10C and alternative D12.16261P.001. It says samples are available now. It does not state a last purchase or last shipment date. Neither March 31 nor the sample statement can fill those missing fields.
There is a second issue to resolve: the opening paragraph calls the alternatives Promos DDR4 DRAMs, while the alternative module’s specification row says DDR3 DIMM. Ask Apacer for clarification and the applicable module specification before treating this as an approved substitution. This page does not choose which description is correct. Read Apacer PCN 202603310001.
Alliance PCN 20240630: a die revision has its own timeline
Alliance Memory’s June 30, 2024 notice covers listed 8Gb DDR4 Rev.0 devices. It sets LTB at December 31, 2024 and LTS at June 30, 2025, and lists Rev.A alternatives. One mapping is AS4C512M16D4-75BCN to AS4C512M16D4A-62BCN. This is a revision-specific transition, not an exit date for all DDR4. The letter asks customers to begin verification of alternatives. Read Alliance PCN 20240630.
A memory module, blank sheets and a pencil on a desk.
Copy the PCN checklist before making a last-time buy
Use one record per complete manufacturer ordering code. A distributor’s stock code can be an additional field; it should not replace the manufacturer code used by the notice. The table below is a blank worksheet, and the downloadable PCN checklist CSV supplies the same fields for multiple BOM lines. Neither is a list of currently available parts.
| Field | Your entry | Evidence needed |
|---|---|---|
| Supplier and full manufacturer part number | Approved BOM and current ordering code | |
| Module or component; revision and suffixes | BOM, identification record and supplier document | |
| Notice number and revision | Complete PCN, including attachments | |
| Notice URL and date retrieved | Saved source copy | |
| Announcement date | Notice date, not a search-result date | |
| LPD/LTB and original label | Explicit deadline and ordering terms | |
| LSD/LTS and original label | Explicit deadline and shipment terms | |
| Recommended replacement part number | Exact mapping in the notice or written supplier answer | |
| Qualification status and owner | Internal review and approval record | |
| Missing or conflicting information | Open question, supplier response and follow-up date |
A completed historical record might read: Micron; MT40A2G4SA-062E:J; PCN 34165; announcement 2021-06-02; LPD 2021-12-02; LSD 2022-06-02; recommended replacement MT40A2G4SA-062E:R; qualification status unknown—requires internal record. That last field cannot be filled from Micron’s replacement column.
For the Apacer example, enter announcement 2026-03-31, leave LPD and LSD blank, and record the generation-description conflict as an open question. A blank means unknown, not permission to keep ordering indefinitely. No Samsung or SK hynix deadline is supplied here because no notice for your exact BOM part has been established by these examples.
When should you keep buying, plan stock, or evaluate a replacement?
Use the document review to choose the next action. These are editorial planning recommendations, not supplier guarantees.
| Situation in your record | Next action | Decision still open |
|---|---|---|
| Exact part not found in the notice | Ask for current lifecycle status for the full code | Whether this BOM line is affected |
| Affected part; deadline or terms missing | Request a written, dated clarification | Purchase window, shipment window and accepted terms |
| Affected part; deadlines documented; build demand continues | Compare the build and service demand plan with the documented windows and confirmed order terms | Stock commitment and exposure if demand changes |
| Alternative named; no internal approval | Assign engineering evaluation and an approval owner | Whether the alternative can enter this BOM |
| Conflicting alternative descriptions | Obtain corrected documentation before approving substitution | Exact replacement identity and specification |
Do not infer a DDR3-to-DDR4 replacement from a marketing label or a PCN sentence. Have engineering reconcile the candidate’s device or module documentation with the actual host design. As a review agenda, record interface support, package or connector, electrical requirements, organization, timing setup, operating conditions, and firmware dependencies; each acceptance criterion belongs to your design documents.
A circuit board in a bench fixture beside a gray ribbon cable.
Keep evaluation access in the plan. The JTAG versus SWD checklist helps document debug and board-test access if a board change is needed; it does not qualify a memory substitute. More design notes are filed under Embedded Systems.
The useful output is a BOM record with a source, a deadline where stated, and an owner for every unresolved question. A general phaseout headline cannot supply those missing fields.
Method and sources
Updated October 15, 2026. This document review uses Micron PCN 34165 from the saved text retrieved October 11, plus Apacer PCN 202603310001 and Alliance PCN 20240630 downloaded and read October 15. A fresh request to Mouser on October 15 returned an access-check page rather than the Micron PDF, so the historical example relies on the earlier saved source. The older notices are retained to explain scope and date labels, not presented as new announcements.
The source links identify manufacturer documents; Mouser and DigiKey host copies. No memory device was tested, no stock was checked, and no supplier’s current order acceptance was established. Check the newest notice and any written amendments for the complete part number before using a deadline commercially. The worksheet and action table are this site’s editorial tools, not a published industry standard.
