Daily component intelligence · 18 September 2026
The short answer: Diodes Incorporated PCN-2759 Rev1 places S1613B-25.0000 and S1613B-25.0000(T) past their 17 September 2026 last-ship date. Buyers may still see residual stock and an “Active” label at an authorized distributor, but those channel fields do not cancel the manufacturer’s EOL notice. Treat available units as time-sensitive residual supply, obtain written order acceptance and traceability, and qualify FN2500400 as a manufacturer-recommended candidate that still requires engineering validation.
What changed on 17 September 2026
Diodes PCN-2759 Rev1 was issued on 17 September 2025. It states that products in its lifetime-buy tables had a last-order date of 17 March 2026 and a last-ship date of 17 September 2026, subject to availability. In Table 4, the manufacturer lists both exact orderable numbers—S1613B-25.0000 and S1613B-25.0000(T)—and maps each one to FN2500400.
That timing matters because a last-ship date is not merely an early warning. It is the end of the manufacturer’s published fulfillment window for accepted lifetime-buy orders. Any product still visible afterward may be distributor-held material, stock already in the channel, or a separate factory-availability field that has not yet caught up with lifecycle data. None of those possibilities should be treated as proof that Diodes has reopened ordering.
The affected S1613 device is a 25 MHz, 3.3 V, surface-mount crystal oscillator with LVCMOS/LVTTL output. The published S1613/FN family data sheet and distributor attributes identify the legacy configuration as a 7 × 5 mm, four-pad package with an enable/disable function. Those visible similarities are useful for planning, but they are not a substitute for comparing the complete legacy and candidate specifications.
Why the channel page still looks “Active”
On 18 September 2026, the DigiKey page for S1613B-25.0000 showed 634 units in stock, a part-status field of Active and a 32-week manufacturer-standard-lead-time field. The separate S1613B-25.0000(T) page showed 210 units in DigiKey stock, a separately labeled factory-stock figure of 20,000 and a 28-week lead-time field.
Those numbers describe different things. “In stock” is visible distributor inventory at that moment. “Factory stock” is a separate field and must not be added to distributor inventory without written confirmation of availability, allocation and ship date. A standard lead-time field is also not a written available-to-promise commitment. Finally, a distributor’s Active attribute can lag the manufacturer’s lifecycle notice.
The practical reading is therefore narrow: residual supply exists in the channel, but its sellability, ownership, lot condition and replenishment path require confirmation. The pages do not prove a global shortage, and they do not prove that 20,000 additional units can be accepted as a new order. Inventory can move quickly, so use the live product page for discovery and a written quotation for the decision record.
A controlled buying plan for the remaining S1613 supply
Procurement teams with an open requirement should work in two tracks. The first track protects near-term production. Ask the authorized seller to confirm the exact MPN, orderable packaging, available quantity, date code, lot traceability, storage condition, manufacturer warranty, country of origin, ship date and whether the order is non-cancellable/non-returnable. Request explicit written confirmation that the order will be accepted after the published last-ship date. Do not rely on a screenshot alone.
Keep the two orderable numbers separate in the BOM and quotation. The parenthesized (T) suffix is part of the manufacturer product number; it must not be stripped during normalization or grouped with the non-parenthesized orderable. The same rule applies to reel, cut-tape and handling options at the distributor level.
The second track limits a future line stop. Freeze demand by build, approved revision and time horizon. Allocate confirmed residual stock only to validated assemblies. If the quantity is below the full requirement, decide whether to reserve it for service obligations, a bridge build or a final production run. Record the source and lot against the affected PCBA so field returns can be traced later.
For an updated quotation, send the exact BOM line, annual usage, build schedule, required packaging, destination and acceptable date-code window. That gives the sourcing team enough information to compare a residual-stock purchase with the cost and timing of an engineering change.
FN2500400 is a candidate, not an automatic drop-in
The PCN calls FN2500400 a recommended replacement and says the listed replacement part numbers are active Diodes-branded devices. The same notice also instructs customers to consult the corresponding published data sheets for compatibility. That caveat is important: “recommended replacement” does not mean every board, firmware timing path and production test limit is already approved.
Start with a controlled comparison of the legacy device and candidate. Confirm the mechanical outline, land pattern, pad numbering, height, packing method and assembly profile. Then compare supply voltage, output logic, enable/disable polarity, startup time, output load, frequency stability across temperature, phase jitter, current consumption and absolute maximum ratings. Check whether the system depends on a specific power-up state or oscillator-enable sequence.
Bench validation should include startup at minimum and maximum supply voltage, the full intended temperature range, output amplitude and duty cycle, clock frequency error, enable/disable behavior and current draw. Where the clock feeds a communications interface, processor or timing-sensitive converter, run the relevant functional and signal-integrity tests. If the product is safety-related, automotive, medical or otherwise controlled, route the change through its existing qualification and documentation process.
Facts, judgment and recommended action
Verified facts
- Diodes PCN-2759 Rev1 gives 17 March 2026 as the last-order date and 17 September 2026 as the last-ship date for the lifetime-buy table.
- The PCN lists both exact 25 MHz S1613 orderable numbers and identifies
FN2500400as the recommended replacement. - On 18 September 2026, the two DigiKey pages still displayed residual stock, Active status and standard lead-time fields; the parenthesized device also showed factory stock separately.
Our judgment
The manufacturer PCN is the controlling lifecycle evidence. Distributor inventory is useful for a bridge purchase, but the visible fields do not demonstrate that new factory orders remain open or that all displayed quantities are immediately deliverable.
Recommended action
Secure written ATP and traceability for any residual buy, preserve the two exact MPNs separately, and start a documented sample qualification of FN2500400. If you want a second set of eyes, send the affected BOM line, PCBA revision, annual demand and validation constraints through our electronic components sourcing team for an updated quotation and engineering review.
Frequently Asked Questions
Is S1613B-25.0000 discontinued?
Yes. Diodes PCN-2759 Rev1 lists S1613B-25.0000 and S1613B-25.0000(T) in its EOL table with a last-order date of 17 March 2026 and a last-ship date of 17 September 2026.
Does an Active distributor status mean the EOL was cancelled?
No. A distributor lifecycle attribute may lag the manufacturer notice. Use the PCN as the lifecycle authority and obtain written order acceptance for any remaining stock.
Is FN2500400 a direct drop-in replacement?
It is the manufacturer-recommended candidate in the PCN, but compatibility still requires data-sheet comparison, PCB review and electrical and system-level validation before BOM approval.
Can DigiKey stock and factory stock be added together?
No. They are separately labeled supply fields. Keep them separate until the seller confirms available quantity, allocation, order acceptance and ship date in writing.
What should a BOM owner do first?
Confirm near-term demand, request written ATP and traceability for the exact MPN, reserve only verified residual stock, and launch a controlled FN2500400 qualification in parallel.
Sources
- Diodes Incorporated, PCN-2759 Rev1: Product End of Life — notification dated 17 September 2025.
- Diodes Incorporated, FN Series / S1613 data sheet.
- DigiKey exact product page: S1613B-25.0000 — checked 18 September 2026.
- DigiKey exact product page: S1613B-25.0000(T) — checked 18 September 2026.
Choose the long-term lifecycle response
This notice is one part-specific event. Use the obsolete and EOL components decision framework to compare a calculated last-time buy, replacement qualification and redesign using the same demand, inventory, timing and approval evidence.
