4A eFuse for 2.7V to 18V rails
The Texas Instruments TPS259541DSGR is an electronic fuse (eFuse) in an 8-WSON package, designed to protect downstream circuitry from overcurrent, overvoltage, and inrush events on supply rails from 2.7V up to 18V. It delivers a continuous 4A output with a current-limit accuracy of ±7.5%, making it a fit for 3.3V, 5V, and 12V bus protection in industrial, telecom, and automotive-adjacent designs.
Input range and load budget
The 2.7V to 18V input span covers common intermediate bus voltages without needing a separate pre-regulator. The 4A continuous rating sets the ceiling for the protected load — derate for ambient temperature above 85°C per the datasheet's SOA curves, since the 8-WSON exposed pad relies on PCB copper area for heat sinking. The ±7.5% current-limit accuracy means a 4A limit can trip as low as 3.7A or as high as 4.3A. Budget the low end when sizing the load: if the load draws 3.5A steady-state, the 3.7A minimum trip point leaves only 200 mA of headroom — marginal under transient conditions.