For electronic components, not recommended for new designs (NRND) means a part is still supplied but discouraged for new products, component end of life (EOL) means withdrawal has been announced, and last-time buy (LTB) is the final ordering window. Each status leaves less time to qualify an alternate before production is affected.
How Do EOL, NRND, and LTB Compare at a Glance?
| Factor | NRND | EOL | LTB |
|---|---|---|---|
| What it means | Still supplied for existing designs; discouraged for new ones | Manufacturer has announced a production withdrawal | Final window to place an order before the stated deadline |
| Time left | No universal deadline; sometimes months or years | Dates set by the product discontinuance notice | Until the last-order date in that notice |
| Can you still order? | Usually, for an existing design | Usually, while the final-order window remains open | Only before the stated deadline, subject to supplier terms |
| Urgency | Plan | Decide | Act before the deadline |
| Best move | Qualify an alternate early | Choose a final buy, alternate, or redesign | Place a justified final order and control the remaining stock |
Lifecycle labels differ across suppliers and data services. Altium warns that aggregated status can lag, so verify the exact orderable number and dates in the manufacturer’s notice.
What Does NRND Mean, and Why Shouldn’t You Ignore It?
NRND is not a stop-ship notice. Existing customers can usually continue to buy the device, while the manufacturer steers new designs toward another part. Texas Instruments describes NRND parts as available for existing designs. Renesas uses the label when a product serves existing customers or when discontinuance is being considered. Neither statement guarantees a date for how long your exact variant will remain orderable.
For a product still in design, NRND should trigger a part-choice review before the layout, firmware, enclosure, and test plan are frozen. A nominally pin-compatible substitute may differ in start-up behavior, thermal performance, tolerance, or package finish. Check those details during design for manufacturing, while a changed footprint or second source is still affordable.
For a released product, find every assembly and board revision that uses the part. Ask engineering whether an alternate has already passed electrical, reliability, and production tests. If it has not, begin qualification while the existing part can still support pilot builds. The avoidable mistake is treating “still purchasable” as “safe for the next five years.” Availability today says little about whether a redesign will arrive before the line needs it.
What Changes When a Part Goes EOL?
A formal discontinuance notice changes the discussion from “what if” to dates and quantities. It should identify the affected manufacturer part numbers and the final date for placing orders. A supplier may also give a final-shipment date, replacement candidates, and terms such as non-cancellable, non-returnable orders. The product team must decide whether to buy enough to finish production, qualify another part, or revise the board. The Renesas lifecycle policy, for example, calls its announced state “EOL-notified” and may use “Obsolete” in the same category name before final orders close.
JEDEC JESD48C sets a minimum of six months from notice to final orders and 12 months from notice to final shipments for the customers and solid-state products in its scope. Later J-STD-048 is used in supplier policies, but a team’s working dates are the dates in its actual notice. Analog Devices gives a 12-month order window and shipments for up to 18 months under its stated policy.
What Is a Last-Time Buy, and How Do You Size One?
An LTB is the last opportunity to place an accepted order for the withdrawing component under the manufacturer’s notice. The last-shipment date is different: a supplier may deliver the final order months after ordering closes. Confirm both dates and any minimum order, allocation, cancellation, or storage terms with the supplier.
A common sizing approach starts with the remaining production forecast through the planned end of the product, adds service spares and expected assembly losses, allows a risk-based buffer, and subtracts usable stock and confirmed open orders. Altium’s BOM risk guidance compares on-hand material and open orders with forecast and service needs before the deadline. This is a decision framework, not an industry-mandated formula. Demand uncertainty, redesign timing, shelf life, and the ability to qualify an alternate should change the number.
Suppose a product needs one chip per unit and the team expects 8,000 more builds. It budgets 400 chips for service spares, 200 for assembly loss, and a 10% buffer on the 8,600-unit base, or 860 chips. The need is 9,460 chips. With 1,500 usable chips on hand and 1,000 confirmed in open orders, the indicative LTB is 6,960 chips. Engineering and procurement should challenge each input before turning that result into a non-cancellable order.
In particular, check whether demand ends when new-product shipments stop or whether warranty repairs continue. Check date codes, moisture sensitivity, packaging, and storage conditions for a multi-year inventory hold. The cash tied up in excess stock can exceed the cost of qualifying a substitute. Too small an order, however, may force a redesign while sales or service obligations continue. Run at least a low- and high-demand scenario and record who accepts the residual risk.
What Happens After the LTB Deadline?
Once the manufacturer stops accepting final orders, new supply from it is no longer a normal catalog purchase. Previously ordered units may still ship before the last-shipment date, and authorized distributors may have traceable stock. A status of “Obsolete” usually means the original manufacturer no longer produces the part, though stock can remain in distribution. Analog Devices uses “Obsolete” for models no longer available from it, while other suppliers can apply that label at a different point in the withdrawal process.
If authorized inventory is exhausted, broker-only offers may be the only apparent source. That changes the quality decision as well as the price. TI warns that parts bought outside authorized channels may be counterfeit or unreliable. Demand original packaging, custody records, lot and date-code information, and a documented risk decision. Expand incoming inspection and appropriate electrical testing for the risk; neither can recreate traceability that never existed.
How Should You Handle These Statuses With a Contract Manufacturer?
Decide ownership before a status alert arrives. Procurement should monitor the released bill of materials for manufacturer notices, distributor status changes, and low-coverage parts. Engineering should judge fit and qualification work for an alternate. The product owner should approve the cost and schedule trade-off. The factory can report exposure and execute the chosen plan, but it should not silently choose a new chip because its buyer found a convenient listing.
Use one record for each affected component: exact manufacturer number, assemblies and revisions using it, notice and dates, on-hand and ordered quantities, proposed alternate, tests required, decision owner, and the effective build. If an alternate changes a released product, approve it through an engineering change order so purchasing, work instructions, test fixtures, and inventory disposition all reference the same revision.
Specify who funds an LTB and who physically stores it. If the contract manufacturer holds customer-owned stock, agree on segregation, traceability, periodic counts, storage conditions, and access if production moves. Confirm whether unused material can be returned, transferred, or scrapped. These details sound administrative until two companies each believe the other one owns 7,000 aging chips.
Titoma’s useful role in this situation is to keep the client’s engineering decision tied to sourcing and production records across its manufacturing partners in Taiwan and China. For a live product, ask for the actual notice, a stock-and-demand calculation, approved alternatives, and the first build affected by any change. That evidence tells you whether “we manage obsolescence” is a working process or a sentence on a slide.
