What kind of malfunctions can occur when the self-resetting fuse of a data center switch fails?

Failure modes of self-resetting fuses in data center switches include: long-term overcurrent causing polymer decomposition into a permanent high-resistivity state (open circuit failure), or lightning surges exceeding the rated breakdown voltage causing carbonization and conduction (short circuit failure). In an open circuit failure, the corresponding port power loss manifests as the indicator light on the switch port going out and communication interruption. In a short circuit failure, the overcurrent protection function is lost; when the back-end circuit is short-circuited, the PTC does not trip, causing the PCB copper foil to melt or the connector to burn out. The Yinte Electronics SMD2920 series is AEC-Q200 certified, with a failure rate of <50 FIT (50 times per 10⁹ hours) under rated conditions. It is recommended that the PTC operating current be dated to below 70% of the nominal value during design; actual measurements show that derating can extend the lifespan by 10 times.