Bourns Current-Sense Resistor PCN: What Should PCBA Buyers Validate Before November 19, 2026?

PCBA buyers using any of the seven orderable part numbers in Bourns Product Change Notification N2649 should complete a documented change review before November 19, 2026. The supplier says the new EBW source and Fe-Cr alloy provide equivalent performance and do not affect form, fit, function, quality or reliability, but it also recommends that customers test the affected parts in their own applications.

This is not an end-of-life notice and it does not automatically require a PCB redesign. It is a controlled supplier-and-material change that should be matched to the exact BOM, qualification requirements and traceability rules of each affected program.

What exactly is changing?

Bourns issued [Product Change Notification N2649](https://www.bourns.com/docs/technical-documents/product-change-notifications/Bourns_N2649_CSS2H-2512K-5L00x_CSI2H-2512K-5L00x_PCN.pdf) on September 2, 2026. The notice covers selected CSS2H-2512K-5L00x and CSI2H-2512K-5L00x current-sense resistors.

The manufacturer describes two linked changes:

- introduction of a new qualified supplier for the electron-beam-welding, or EBW, raw material; and - transition of the resistive element to a different Fe-Cr alloy that Bourns says has equivalent performance characteristics to the current alloy.

Bourns states that the manufacturing process will remain the same. It also states that the changes do not affect form, fit, function, quality or reliability, and that qualification was completed to AEC-Q200 requirements.

The notice does not say that the products are being discontinued. It also does not announce a price change, shortage, allocation or lead-time extension.

What are the confirmed dates and traceability markers?

As of September 29, 2026, buyers have 51 days before the stated implementation date.

- Notice issue date: September 2, 2026. The published change record is already available for review. - Current-supplier deliveries cease: November 18, 2026. Do not assume every lot received before this date uses the current source; verify the supplier's traceability data. - New-supplier deliveries begin: November 19, 2026. Post-change material can begin entering the supply chain from this date. - First date code using the changes: 2647. Add the manufacturer's date-code information to incoming and production traceability records. - Samples: available upon request. Request samples early enough to complete any required comparison testing. - Qualification report: available upon request. Obtain and review the evidence required by the customer's change-control process.

The buyer interpretations above are industry analysis, not additional commitments from Bourns.

Which orderable part numbers are affected?

The official notice lists seven exact part numbers:

CSS2H-2512K-5L00x family:

- CSS2H-2512K-5L00F - CSS2H-2512K-5L00J - CSS2H-2512K-5L00FE - CSS2H-2512K-5L00JE

CSI2H-2512K-5L00x family:

- CSI2H-2512K-5L00F - CSI2H-2512K-5L00J - CSI2H-2512K-5L00G

Match the complete manufacturer part number. A family-level search for “CSS2H-2512” or “CSI2H-2512” can create false positives because Bourns publishes other resistance values, tolerances and packaging options within these series.

Does “no form, fit or function change” mean no buyer action is needed?

No. It means Bourns does not expect the listed product characteristics to change; it does not remove the customer's responsibility to approve a supplier or material change under the rules of the intended application.

The PCN itself makes that distinction. Bourns says traceability will be maintained through date code, makes samples and a qualification report available on request, recommends testing the affected part numbers in the customer's application, and tells users to verify that the change will not affect product performance in their specific applications.

The practical response should be proportionate to risk:

- A commercial product with wide electrical margin may need a document review, exact BOM match and traceability update. - A calibrated current-measurement circuit may need comparative electrical and system-level checks. - An automotive, safety-related or customer-controlled program may require formal change approval, evidence review and customer-specific records before post-change material is released.

These are examples of risk-based industry practice. They are not a claim that Bourns requires the same validation package for every application.

What should PCBA buyers do before November 19?

1. Match the PCN to released and service BOMs

Search production, NPI, repair and service BOMs for all seven exact orderable numbers. For every match, record the assembly revision, approved manufacturer list status, program owner, current inventory, open purchase orders and production dates that may cross November 19.

Do not rely only on a distributor description or a shortened series name. Retain the manufacturer part number shown in the controlled BOM and purchase record.

2. Request the manufacturer's evidence

The notice says samples and the qualification report are available on request. Ask Bourns or an authorized distributor for the documents and material needed by the applicable customer, quality system or approval process.

At minimum, the review package may include:

- PCN N2649 and the internal change assessment; - the qualification report supplied for this change; - the current and updated material declaration, where required; - sample-lot identification and date-code information; - the affected BOM and approved manufacturer list entries; and - the customer or engineering approval record.

Availability of a report or sample does not by itself constitute customer approval.

3. Define the validation plan by circuit risk

Because these are current-sense components, a sensible engineering review may consider the measured resistance in the actual sensing path, thermal behavior at operating load, calibration margin, reflow exposure, solder-joint quality and system output across the intended operating range.

Possible checks include:

- Incoming verification: Can the lot, date code and source transition be traced to the manufacturer's records? - Electrical comparison: Does the sample lot remain within the approved component and system-level limits? - Thermal performance: Is self-heating acceptable at the assembly's actual current and ambient conditions? - Assembly process: Does the existing stencil, placement, reflow and inspection plan remain suitable? - Functional test: Will the current-measurement or protection circuit detect unacceptable drift? - Customer requirements: Does the program require notification, PPAP-related evidence or written approval before use?

This is a risk-screening checklist, not a substitute for the component data sheet, the customer's specification or the manufacturer's qualification report.

4. Keep pre-change and post-change lots identifiable

Bourns states that traceability will be maintained through date code and identifies 2647 as the first date code using the changes. Procurement and manufacturing teams should retain lot and date-code data at receiving, material issue, assembly and finished-goods release where the program requires controlled traceability.

If both pre-change and post-change inventory are present, define whether they may be commingled. Do not create a segregation requirement unless the customer's engineering or quality decision calls for one, but do not lose the ability to reconstruct which lot entered which build.

5. Update the change record without inventing a new part number

The PCN lists the affected orderable part numbers; it does not direct buyers to a replacement number. Unless Bourns or the customer's controlled documentation says otherwise, the task is to record the approved change against the existing manufacturer part number, not to create an unsupported substitute.

Typical records to review are:

- BOM and approved manufacturer list; - supplier and PCN register; - incoming inspection and traceability instructions; - control plan and work instructions; - assembly and functional-test criteria; - deviation, change approval or customer notification record; and - first production lot after the change.

6. Check open orders that cross the implementation date

Ask the authorized source what lot and date-code information will accompany scheduled deliveries. A purchase-order date alone may not establish whether the material is pre-change or post-change.

If the program requires approval before post-change material is used, align the approval milestone with the expected receipt and production schedule. The official notice provides implementation dates but does not promise distributor inventory timing.

Does this PCN require a PCB layout change?

Based on the manufacturer's statement that form, fit and function are unaffected and the manufacturing process remains the same, the notice does not indicate a mandatory footprint or PCB layout change.

However, “no layout change” and “no validation” are not the same conclusion. A low-ohmic current-sense component can influence measurement accuracy, protection thresholds and thermal performance even when its package and nominal function remain unchanged. The appropriate decision is to preserve the existing design if the evidence and application testing support approval, rather than redesigning automatically or approving automatically.

What is fact, what is analysis, and what can JETFGO support?

External fact

Bourns N2649 lists seven affected orderable part numbers; states that current-supplier deliveries cease November 18, 2026; starts new-supplier deliveries November 19; identifies first date code 2647; reports AEC-Q200 qualification; says form, fit, function, quality and reliability are unaffected; and offers samples and a qualification report on request.

Industry analysis

Buyers should perform an exact BOM match, obtain evidence, use a risk-based test plan, control lot/date-code traceability and align approval with the production schedule. These are procurement and quality recommendations, not Bourns commitments.

JETFGO's published capability

JETFGO publicly describes BOM-based [electronic component sourcing](https://jetfgo.online/en/products/component-sourcing), traceability review and supply coordination connected to [PCB assembly and PCBA services](https://jetfgo.online/en/products/pcb-assembly). Its published [PCB engineering solutions](https://jetfgo.online/en/solutions) emphasize document control, traceability and repeatability for applications including automotive and power electronics.

These published capabilities do not mean JETFGO can approve the Bourns change for a customer, guarantee a specific lot or replace the manufacturer's qualification evidence. Final approval depends on the exact BOM, application, customer requirements and current authorized-channel information.

What should you send for a PCBA change review?

Prepare one controlled package containing:

1. the released BOM and exact affected Bourns part number; 2. PCN N2649 and any qualification evidence received from Bourns; 3. the product and PCBA revision, open-order schedule and required approval date; 4. schematic information for the current-sense or protection circuit; 5. operating-current, temperature and calibration limits relevant to validation; 6. incoming, assembly and functional-test requirements; and 7. customer-specific notification, traceability or PPAP requirements, if applicable.

For a sourcing and manufacturing review, use JETFGO's [factory-direct RFQ contact page](https://jetfgo.online/en/contact). The purpose of the review is to connect the component change to the correct purchasing, assembly, traceability and test controls—not to replace the component manufacturer's evidence or the customer's engineering approval.

Bottom line

Bourns N2649 is a change-control event, not an end-of-life event. Seven CSS2H/CSI2H 2512 current-sense resistor orderable numbers move to a new qualified EBW source and a different Fe-Cr alloy beginning November 19, 2026, with first date code 2647.

Buyers should use the remaining review window to match exact BOMs, request samples and qualification evidence, define proportionate application testing and preserve lot/date-code traceability. The best outcome is not the largest test plan; it is an evidence-backed approval completed before post-change material reaches production.

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