Research Report on the Aging Behavior of the MBRF10200CT Plastic‑Encapsulated Schottky Diode Under Different Input Voltages

Abstract: This research report presents an in-depth investigation into the phenomenon whereby the MBRF10200CT plastic‑encapsulated Schottky diode exhibits no reliability issues when subjected to 120 V input during aging tests, yet fails to deliver output after approximately ten minutes of operation at a 277 V input. Through analysis of the issue and experimental validation, the study proposes immediate corrective actions, remedial measures, and preventive strategies to enhance the product’s stability and reliability.

Research Report on the Aging Behavior of the MBRF10200CT Plastic‑Encapsulated Schottky Diode Under Different Input Voltages

Abstract: This research report presents an in-depth investigation into the phenomenon whereby the MBRF10200CT plastic‑encapsulated Schottky diode exhibits no reliability issues when subjected to 120 V input aging, yet fails to deliver output after approximately ten minutes of aging at 277 V. Through analysis of the issue and experimental validation, the study proposes immediate corrective actions, remedial measures, and preventive strategies to enhance the product’s stability and reliability.

I. Introduction

The MBRF10200CT plastic‑encapsulated Schottky diode plays a critical role in power supply systems. During product aging tests, it was observed that the diode exhibited normal aging behavior when the input voltage was 120 V; however, when the input voltage was increased to 277 V, the power supply developed a no‑output fault after approximately ten minutes of operation. To identify the root cause, resolve the issue, and prevent recurrence, this study was conducted.

II. Problem Description

In the power‑supply aging test, a power‑supply system employing MBRF10200CT plastic‑encapsulated Schottky diodes was subjected to prolonged aging at an input voltage of 120 V, with no abnormalities observed and stable output. However, when the input voltage was increased to 277 V, after just over ten minutes of operation, the output abruptly dropped to zero, resulting in a loss of normal power delivery.

III. Cause Analysis

(1) Insufficient diode parameters

The rated voltage, current, and other parameters of the MBRF10200CT plastic‑encapsulated Schottky diode may not meet the operating requirements under a 277 V input voltage. Under high‑voltage input conditions, the diode could experience excessive reverse voltage that exceeds its reverse breakdown voltage, leading to device failure and resulting in no output from the power supply.

(II) Thermal Effects Issues

At a high input voltage of 277 V, the MBRF10200CT plastic‑encapsulated Schottky diode experiences increased power losses during operation, causing the junction temperature to rise rapidly. If thermal dissipation is inadequate, heat buildup may drive the diode’s junction temperature beyond its maximum allowable limit, leading to performance degradation or even device failure and resulting in no output from the power supply.

(3) Manufacturing Process Defects

Diodes may exhibit manufacturing defects, such as poor chip bonding, non-uniform packaging materials, or microscopic voids. These defects might remain undetectable at an input voltage of 120 V; however, under a high‑voltage input of 277 V, the increased electric field strength and thermal stress can accelerate degradation at the defect sites, leading to diode failure and resulting in no output from the power supply.

(4) Unreasonable circuit design

The power‑supply circuit design may contain deficiencies, such as improper diode placement and routing, which can lead to uneven voltage distribution across the diodes under high‑voltage input conditions, resulting in localized overvoltage. Alternatively, inadequate protective measures for the diodes may leave them vulnerable to damage under abnormal voltage conditions, ultimately causing the power supply to fail to deliver output.

IV. Immediate Action Plan

(1) Stop aging test

Once it is detected that the power supply loses output during the 277 V input voltage aging process, the aging test should be stopped immediately to prevent further deterioration and damage to other equipment.

(2) Perform diagnostics on the faulty power supply.

Use instruments such as a multimeter and an oscilloscope to test the faulty power supply, measuring parameters of the MBRF10200CT plastic‑encapsulated Schottky diode—including forward voltage drop, reverse leakage current, and reverse breakdown voltage—to determine whether the diode is damaged.
Inspect other components in the power circuit, such as resistors, capacitors, and inductors, to determine whether they are damaged or exhibiting abnormal performance.

(3) Replace the damaged diodes.

If the MBRF10200CT plastic‑encapsulated Schottky diode is found to be damaged during inspection, it should be replaced immediately with a new diode of the same model. During replacement, pay close attention to soldering procedures and electrostatic discharge (ESD) protection to ensure proper and reliable installation.

(4) Aging Recovery Test

After replacing the diodes and conducting a thorough inspection of the power supply circuit, the aging test was repeated. First, an aging test was performed at a lower input voltage (e.g., 120 V) for a specified duration; once the power supply output was confirmed to be normal, the input voltage was gradually increased to 277 V, and the power supply’s operating condition was monitored to ensure that the issue had been resolved.

V. Corrective Measures

(1) Re-selection of models

The MBRF10200CT plastic‑encapsulated Schottky diode has been reselected; a diode with higher rated voltage, current, and other parameters has been chosen to meet the operating requirements under a 277 V input voltage. For example, a Schottky diode with a rated voltage of 300 V or higher could be selected.

(II) Optimizing the Thermal Design

Add a heat sink: Attach an appropriately sized heat sink to the diode to increase the heat-dissipating surface area and enhance thermal efficiency.
Improve airflow design: Optimize the internal airflow paths within the power supply to ensure that cool air flows smoothly over the diodes and other heat-generating components, effectively removing heat.

(3) Strengthen quality control throughout the manufacturing process

Strengthen quality monitoring throughout the diode manufacturing process, rigorously control the quality of key process steps such as chip bonding and encapsulation, and ensure that products meet applicable quality standards.
Increase the number of factory‑acceptance test items and the sampling rate for diodes to enhance product reliability.

(4) Optimize the circuit design

Properly position diodes within the circuit to ensure uniform voltage distribution; optimize routing to minimize trace impedance and parasitic inductance, thereby reducing voltage stress on the diodes.
By incorporating overvoltage protection, overcurrent protection, overheating protection, and other protective circuits into the circuit, the diodes are effectively safeguarded, thereby enhancing the stability and reliability of the power supply system.

VI. Measures to Prevent Recurrence

(1) Establish a rigorous quality management system

Establish detailed quality control procedures and standards to implement comprehensive quality management across all stages, including raw material procurement, manufacturing, product inspection, and packaging and transportation.
Strengthen supplier management by establishing a supplier evaluation and audit mechanism to ensure the consistent quality and reliability of raw materials.

(II) Strengthen Employee Training

Regularly organize skill‑training and quality‑awareness sessions for employees to enhance their professional competencies and quality consciousness.
Provide employees with training on new products and technologies, enabling them to promptly acquire the latest knowledge and skills and better meet production requirements.

(3) Establish a product reliability testing system

Establish a comprehensive product reliability testing platform to conduct thorough reliability assessments on new products, including high-temperature aging tests, thermal cycling tests, vibration tests, and shock tests, ensuring that the products function reliably under a wide range of harsh environmental conditions.
Collect, analyze, and evaluate product reliability data to promptly identify potential quality issues and implement appropriate corrective measures.

(4) Continuous Improvement

Regularly summarize and analyze the product’s quality status, identify existing issues and areas for improvement, develop action plans, and continuously monitor the effectiveness of these improvements to steadily enhance product quality and reliability.

VII. Experimental Verification

To verify the effectiveness of the aforementioned handling plan, corrective measures, and preventive measures against recurrence, we conducted the following experiments:

(1) Experimental Design

Ten power supplies employing MBRF10200CT plastic‑encapsulated Schottky diodes were selected as the experimental sample and divided into two groups, with five units in each group.
The first group of power supplies was subjected to aging tests using the original design (i.e., without any modifications), with input voltages of 120 V and 277 V. The output performance of the power supplies and the operating parameters of the diodes were recorded.
The second batch of power supplies was subjected to aging tests using an improved design—incorporating component re‑selection, optimized thermal management, enhanced manufacturing‑process quality control, and refined circuit‑design optimizations—with input voltage and test procedures identical to those used for the first batch.

(II) Experimental Results

During the aging test, the first group of power supplies exhibited normal output and stable diode operating parameters at an input voltage of 120 V. However, at an input voltage of 277 V, after more than ten minutes of aging, four units lost output; subsequent testing revealed that the diodes in all four cases had failed.
During the aging tests conducted at input voltages of 120 V and 277 V, the second power supply unit exhibited normal output performance, with stable diode operating parameters and no signs of damage.

(3) Experimental Analysis

Experimental results demonstrate that, through measures such as re‑selecting components, optimizing the thermal design, strengthening quality control during manufacturing, and refining the circuit design, the issue of no output from the MBRF10200CT plastic‑encapsulated Schottky diode under 277 V input—caused by aging—can be effectively resolved, thereby enhancing the product’s reliability and stability.

VIII. Conclusion

Through a study of the aging behavior of the MBRF10200CT plastic‑encapsulated Schottky diode under various input voltages, we identified the root cause of the issue and proposed an immediate corrective action plan, along with remedial measures and preventive strategies to avoid recurrence. Experimental verification confirms that these solutions and measures are effective, addressing the existing problems while enhancing product quality and reliability. Moving forward, in both production and application, we will adhere strictly to the revised procedures and controls to ensure product performance and quality, thereby delivering even higher‑quality products and services to our customers.