Supplier EOL and Last-Time-Buy Checklist

What an EOL or discontinuance notice is

When a manufacturer discontinues a part, it issues a product discontinuance notice (PDN), the discontinuance counterpart to a product change notice. Semiconductor discontinuance notices follow JEDEC J-STD-048, and most manufacturers publish their own notification policy on top of it.

A typical notice lists the affected manufacturer part numbers, a suggested replacement if one exists, and the dates that define your response window. Some arrive by email to registered customers, some only appear on a manufacturer portal, and some reach you through a distributor.

The dates that matter

Three dates do the work on a discontinuance notice, and confusing them is expensive:

• +Last-time-buy (LTB) date: the deadline to place final orders. This is the date to plan backwards from, because the demand analysis, funding, and purchase order all have to be finished before it.
• +Last-ship date: the last date the manufacturer will ship. It usually falls months after the LTB date, and it constrains delivery scheduling of the final order, not the decision itself.
• +Effective date: on a change notice, the date the change takes effect in shipped product. Discontinuance notices may also carry an end-of-support or obsolete date.

Last-time buy, alternate, or redesign

Each disposition trades money against time and risk. A last-time buy is the fastest to execute, but it ties up cash, assumes your demand forecast holds, and raises shelf-life and storage questions for long horizons. Qualifying an alternate takes engineering effort and may trigger customer or regulatory requalification. A redesign is the slowest and most expensive, and sometimes the only durable answer.

The options also combine. A common pattern is a bridge buy sized to cover production while an alternate qualifies, so the LTB order does not have to carry the whole remaining life of the product.

Common failure modes

The same misses come up repeatedly across teams:

• +The notice sits unread in one person's inbox until after the LTB date.
• +An MPN suffix or packing-code difference hides a real BOM match during the cross-check.
• +Inventory is checked but service and repair demand is forgotten, so the buy is undersized.
• +Everyone agrees action is needed but no single owner is named, and the order is placed late or not at all.
• +The last-ship date is mistaken for the ordering deadline.
• +A sound decision is made but never documented, so the analysis is redone from scratch when a customer asks about the part a year later.

Where PCNshark fits

PCNshark handles the mechanical part of the checklist below: it extracts the affected MPNs and the last-time-buy, last-ship, and effective dates from the notice, matches the MPNs against your monitored BOMs, and keeps the deadline, the owner, and the disposition attached to the original document. For the alternate step, it surfaces the manufacturer's recommended replacement and spec-ranked candidates (Team plans and above), with distributor stock and lead-time estimates as context. The demand analysis and the disposition decision stay with your team, which is where they belong.