Regarding FS32K144HFT0MLLR Circuit Anomaly & Request for Analysis

TonyLi1 — Wed, 30 Apr 2025 07:34:05 GMT

Dear support team,

Hope this email finds you well. We are reaching out regarding an issue encountered during the production of our product involving the FS32K144HFT0MLLR microcontroller, and we kindly request your expertise in troubleshooting the root cause.

### Issue Description:

A circuit anomaly was detected where the **impedance to ground of the VLDO 5V line** showed abnormal readings. Detailed analysis of defective samples revealed the following key findings:

1. **No process-related correlations**: Production process audits confirmed no anomalies in soldering, assembly, or handling procedures that could explain the issue.

2. **X-ray inspection results**: Visual inspection via X-ray imaging of defective units showed no soldering defects (e.g., short circuits, solder bridges, or component misalignment).

3. **Electrical measurements**:

- Samples with the **defective FS32K144HFT0MLLR** exhibited abnormal low impedance on the VLDO 5V ground path (see Figure 1 for test results).

- Replacing the defective microcontroller with a **qualified FS32K144HFT0MLLR** restored normal impedance values (see Figure 2).

- Reinstalling the same defective unit reproduced the abnormal impedance issue, confirming the problem **is isolated to the specific microcontroller units**.

### Request for Assistance:

Given that the defect "follows" the defective microcontrollers (i.e., the issue persists with the same units and resolves with replacements), we suspect a potential **internal component failure** or **manufacturing defect** within the FS32K144HFT0MLLR devices. Could you please help us:

- Identify possible causes for the low impedance on the VLDO 5V ground path from a chip-level perspective (e.g., internal circuitry shorting, component damage, or design-related issues)?

- Suggest recommended tests or analysis methods to validate the root cause (e.g., ATE testing, material analysis, or failure mode simulation)?

We have attached the test result diagrams (Figure 1 & 2) and can provide physical samples for further inspection if needed. Your prompt input would be highly valued to help us resolve this issue and prevent future occurrences.

Thank you for your support, and we look forward to your professional insights.

Best regards！

此致！

Re: Regarding FS32K144HFT0MLLR Circuit Anomaly & Request for Analysis

TonyLi1 — Wed, 30 Apr 2025 07:57:39 GMT

Re: Regarding FS32K144HFT0MLLR Circuit Anomaly & Request for Analysis

guoweisun — Tue, 06 May 2025 00:25:28 GMT

您能提交ticket通过下面的途径吗？

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Re: Regarding FS32K144HFT0MLLR Circuit Anomaly & Request for Analysis