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ziven.wu@cstcomponents.comOlder date code DIODES components should be assessed against the requirements of the specific purchase. Begin with the exact device and offered lot, then examine the available storage evidence, packing condition, assembly requirements, and customer acceptance terms. Record what supports the decision and which questions remain unresolved.
For buyers supporting maintenance, shortages, or a continuing production program, the useful question is whether the identified material can meet an agreed acceptance plan. This guide develops that purchasing review. Manufacturer findings are referenced separately from the suggested decision framework below.
1. Define What “Older Date Code” Means for the Order
Convert a general request for “recent stock” into a clear requirement. Specify an acceptable year or week range, whether age is assessed at dispatch or receipt, and whether different dates or lots may be combined. Identify who can approve an exception before asking suppliers to quote material outside that range.
Keep the manufacturer ordering code unchanged throughout the review. Our DIODES part-number and ordering-suffix guide explains the identity checks that should precede a condition assessment.
AP02006 Rev. 32 distinguishes the external part number from an internal House Number and specifies a YYWW date-code field within the lot reference. [2] Request complete label images and retain the full references. A year-only stock-list entry is insufficient when the order restricts particular weeks or lots.
2. Make Four Separate Acceptance Decisions
Use separate review fields so that a satisfactory answer in one area does not silently close another. The following is a suggested procurement tool; the customer's specification and responsible quality authority determine the actual acceptance requirements.
| Review area | Evidence to request | Decision to record |
|---|---|---|
| Identity | Complete ordering code, package, labels, lot references, and source documents required by the customer. | Does the offered material match the approved item? |
| Storage and handling | Available records for storage, opening, resealing, and other handling, with gaps disclosed. | Are the relevant conditions sufficiently established? |
| Assembly readiness | Applicable moisture instructions, packing and terminal condition, and agreed assessment results. | Can the assembly team accept the material for its intended process? |
| Purchase terms | Date restrictions, document requirements, and written approval of permitted exceptions. | Is this particular purchase authorized under the agreed conditions? |
A supplier statement such as “original stock” should therefore lead to specific supporting questions. Likewise, permission to buy an older year should leave the technical and condition review visible.
3. Read the DIODES Storage Study Within Its Scope
DIODES' September 29, 2025 shelf-life report examines finished goods aged two to three years under controlled storage conditions. It describes packaging, solderability, electrical, and reliability evaluations. Its conclusion supports at least three years of shelf life under the studied conditions, with no failures solely attributable to age observed in the evaluated material. [1]
For a purchasing decision, compare that scope with the offer. A 2019 date code presented in 2026 is beyond the study's evaluated age range. The report cannot close that gap or establish where the offered reels have been stored. Equally, three years should not be turned into a universal failure date: evidence outside the study's scope needs its own assessment.
Ask the quality reviewer to identify what additional evidence, clarification, or evaluation is needed for the actual material. Keep that decision tied to its part number, lot, quantity, and intended use. Do not substitute a general manufacturer publication for the lot-specific acceptance record.
4. Separate Sealed-Bag Shelf Life from Product Age
AP02006 Rev. 32 states that MSL 3 finished goods manufactured and initially sealed after January 1, 2026 have bags stating a calculated 36-month shelf life. Earlier manufactured and sealed MSL 3 inventory remains in its existing bags without repacking or relabeling under this update. [2]
Check the actual device classification, bag information, and handling instructions before applying that provision. It does not establish an unrestricted exposure allowance after opening, and a later resealing entry does not change the component's original date code.
If a bag has been opened, ask what is known about the intervening handling and who performed any subsequent processing. Have the assembly or quality team determine the applicable response. A generic drying recipe should not be added to a purchasing instruction without reviewing the device and packing requirements.
5. Request Evidence That Answers the Storage Questions
Start with the uncertainty you need to resolve. Requesting “all documents” often produces a large file without establishing whether its contents cover the offered material.
Material connection: ask which reels, bags, or trays each record identifies.
Time coverage: establish the periods covered by available storage or handling records.
Packing events: request disclosed opening, splitting, resealing, or repacking information.
Current condition: obtain clear photographs of the actual packing units and any observed damage.
Document scope: identify the issuer and what each certificate or report actually attests.
Record missing periods as missing. A photograph of today's warehouse cannot document an earlier owner's storage, and a replacement label cannot reconstruct an unrecorded opening history. The reviewer should decide whether the remaining gaps can be resolved within the project's requirements.
6. Include the Carrier and Assembly Process in the Review
The DIODES study also examined labels, moisture-barrier bags and humidity indicators where applicable, and tape-and-reel peel performance. [1] This provides context for reviewing the packing that accompanies the components.
Ask the receiving and assembly teams to identify the checks needed for the offered delivery format. These may include visible terminal condition, carrier damage, tape condition, and the moisture-handling information applicable to that device. Preserve packing-unit identities if the material is split for evaluation.
Define the purpose of any additional inspection before commissioning it. Record the question, method, conditions, criteria, and material covered. Keep a passing result within that stated scope. Selected electrical checks, for example, should not be described as verification of every earlier storage event.
Detailed sampling plans require a separate quality review. This purchasing framework does not prescribe a universal sample size or promise a particular inspection service.
7. Use Explicit Release, Hold, and Rejection Decisions
The table below helps turn the review into an action that purchasing and receiving can both follow. Apply the customer's governing procedure and obtain the required approvals.
| Finding | Disposition | Required next step |
|---|---|---|
| Requirements are met and required evidence is complete. | Release for the identified use. | Record authorized approval and the covered lots and quantities. |
| A permitted date-code exception awaits approval. | Hold. | Obtain written approval before release. |
| Storage information or packing records are incomplete or contradictory. | Hold. | Define the clarification or evaluation needed and assign an owner. |
| A mandatory condition is unmet and no deviation is permitted. | Decline the offer or reject the nonconforming delivery. | Record the unmet condition and follow the agreed disposition process. |
| Identity questions remain unexplained or agreed checks fail. | Segregate and hold for investigation. | Follow the quality disposition; reject where required by the agreed criteria. |
Any approval should state its scope. Permission for one lot, quantity, and application should not become blanket approval for every subsequent offer carrying the same part number.
8. Worked Example: A 2019 Offer Against a Newer-Date Requirement
Illustrative scenario: a buyer needs 6,000 pieces of 74AUP2G125RA3-7. The purchasing specification requires 2021 or newer material, while the supplier offers 2019 stock with label photographs and a recent dispatch record.
First, retain the 2019 code in the review. The recent dispatch record does not satisfy the newer-date requirement. Ask whether the customer's procedure permits a deviation and identify the person authorized to approve it.
If a deviation is permitted, hold release while the offered lots, storage evidence, packing condition, and required evaluations are reviewed. A favorable assessment and written date exception are separate items in the approval record. If no deviation is allowed, decline this offer and continue sourcing against the original requirement.
The manufacturer's three-year study cannot independently approve this older material. The scenario describes a decision process and does not represent current CST stock or an acceptance recommendation for a real lot.
9. Put the Accepted Conditions in the Purchase Order
Carry the review into the transaction. Specify the complete ordering code, accepted date codes, quantities by lot, packing format, required documents, and agreed acceptance conditions. Include the reference and scope of any approved exception.
Require disclosure if the proposed source, lot, or packing changes before shipment. Review the revised offer rather than assuming that an earlier approval covers different material. On receipt, reconcile labels, quantities, and reports with the acknowledged order before issuing the goods to production.
When comparing prices, include agreed evaluation, handling, logistics, and schedule costs. Identify uncertain estimates separately. A lower unit price is useful only when the resulting purchase can meet the project's accepted requirements.
10. Prepare a DIODES Inquiry That Can Be Evaluated
CST Components supports electronic-component sourcing with stock and supply coordination in Hong Kong and Shenzhen. For 74AUP2G125RA3-7 or other DIODES requirements, provide:
The complete manufacturer part number and required quantity.
Accepted date-code range and any single-lot restriction.
Full-reel, partial-reel, or cut-tape acceptance.
Required photographs, documents, and inspection conditions.
The approval process for older dates or other permitted exceptions.
Target delivery date and destination.
Email ziven.wu@cstcomponents.com with your requirement. Actual availability, lot details, supporting records, inspection arrangements, and delivery timing should be confirmed for the specific offer.
Frequently Asked Questions
Are DIODES components automatically unusable after three years?
The cited study should not be converted into a universal expiry rule. Review the actual material, applicable instructions, customer requirements, and evidence needed for the proposed use.
Can a passing test override a customer date-code restriction?
Keep technical evaluation and purchasing permission separate. Obtain an authorized deviation where the customer's procedure permits one; otherwise follow the original restriction.
Does an unopened-looking bag establish the complete storage history?
Record its observed condition and available supporting evidence. Appearance alone cannot establish every earlier handling event or environmental condition.
Can a recent resealing date be quoted as the component year?
Retain the component date and resealing event separately. Describe the offered material accurately and disclose the packing history required by the purchase.
