Corrosion A Common Problem in MBRS360T3G Schottky Diodes

Analysis of Failure Causes and Solutions for "Corrosion: A Common Problem in MBRS360T3G Schottky Diode s"

1. Introduction to the Problem

The MBRS360T3G Schottky diode is widely used in Power conversion circuits, rectification, and various applications due to its fast switching capabilities and low forward voltage drop. However, one common issue reported in these diodes is corrosion, which can lead to performance degradation or complete failure. Understanding the causes of corrosion and knowing how to resolve the issue can help in maintaining the reliability of the circuit.

2. Causes of Corrosion in MBRS360T3G Schottky Diodes

Corrosion in Schottky diodes like the MBRS360T3G typically occurs due to the following reasons:

a. Environmental Factors Humidity: Excessive moisture in the surrounding environment can cause corrosion on the metal surfaces of the diode, particularly at the junctions. If the diode is exposed to high humidity for an extended period, the metal terminals may begin to oxidize, leading to corrosion. Temperature Extremes: High temperatures or rapid temperature cycling can cause physical stress on the diode’s material, leading to expansion and contraction of components, which accelerates corrosion. Pollution: The presence of corrosive gases like sulfur or chlorine in the air can accelerate the corrosion process, especially on the leads or exposed metal parts of the diode. b. Improper Handling Moisture Exposure During Soldering: If the diode is exposed to moisture during the soldering process or during storage before installation, corrosion can start to form on the metal leads. Incorrect Storage: If diodes are stored in non-controlled environments with fluctuating humidity or exposed to corrosive substances, this can initiate corrosion on the component. c. Overvoltage/Overcurrent When the diode is exposed to voltages or currents higher than the rated values, it can lead to overheating. This overheating can cause the diode casing to degrade or lead to internal chemical reactions, further exacerbating the corrosion process.

3. How to Detect Corrosion in MBRS360T3G Schottky Diodes

Visual Inspection: Look for visible signs of corrosion such as discoloration or greenish deposits on the metal leads or package. Electrical Testing: Test the diode using a multimeter to check for proper forward voltage drop. Corrosion often leads to increased resistance, making the diode fail to conduct properly. Temperature Measurement: During operation, check for unusual heating of the diode, which can indicate a degraded internal structure due to corrosion.

4. Solutions and Troubleshooting Steps

If corrosion is detected in the MBRS360T3G Schottky diode, here’s a step-by-step guide to resolve the issue:

a. Preventive Measures: Proper Storage: Always store the diodes in a controlled environment with a low humidity level. Use moisture-proof packaging like desiccants and sealed bags. Proper Soldering Environment: Ensure that the soldering environment is free from moisture, and use flux that doesn’t leave behind corrosive residues. Use of Conformal Coatings: Apply a conformal coating to the diode and surrounding components. This coating acts as a protective barrier against moisture and environmental contaminants. b. Immediate Troubleshooting and Resolution: Power Off the Circuit: Always ensure that the circuit is completely powered off before attempting any repair work. Remove the Damaged Diode: If corrosion is observed, carefully desolder the diode from the circuit board using desoldering tools. Clean the Area: Use isopropyl alcohol (IPA) to clean the PCB and remove any corrosive residues. If necessary, use a soft brush to gently clean the area around the damaged diode. Inspect for Damage: Before installing a new diode, inspect the board for signs of other damage, such as burnt traces or other corroded components. Install a New Diode: Install a new MBRS360T3G Schottky diode. Ensure the leads are inserted correctly, and apply fresh solder carefully to avoid overheating the new component. Reflow Soldering: If possible, use reflow soldering instead of hand soldering to prevent excess heat exposure to the diode, which could cause further damage. c. Long-Term Solutions: Use of Diodes with Higher Protection Ratings: Consider switching to Schottky diodes that offer better resistance to environmental factors, such as those rated for higher humidity or with additional protective coatings. Add Moisture Sensor s: In applications where corrosion is likely, use humidity and moisture sensors around the components to detect and mitigate the problem early.

5. Conclusion

Corrosion in MBRS360T3G Schottky diodes is a common problem that is usually caused by environmental factors, improper handling, or exposure to excessive current/voltage. By recognizing the early signs of corrosion and implementing preventive measures, the reliability of the diode and the circuit as a whole can be maintained. Regular maintenance, proper storage conditions, and cleaning procedures will also help ensure the longevity and optimal performance of the diodes.

By following these simple steps and solutions, you can avoid the negative effects of corrosion and ensure a stable and efficient circuit design.