Small-signal N-channel for load switching and level translation
The Infineon BSS138N E8004 is a SIPMOS N-channel MOSFET in a SOT-23-3 package rated for 60 V drain-source and 230 mA continuous drain current. It is designed for low-power load switching, signal-level translation, and general-purpose switching where board space is tight.
Logic-level gate drive — can your GPIO switch it?
The drive voltage range of 4.5 V to 10 V for achieving rated Rds(on) means this part works with standard 5 V logic and 3.3 V logic with marginal headroom. The maximum gate threshold voltage is 1.4 V at 250 µA, so a 3.3 V GPIO will turn it on hard enough for most sub-100 mA switching tasks. For 230 mA loads, use 5 V gate drive to keep Rds(on) near its 3.5 Ohm maximum.
Thermal and switching — what 360 mW and 1.4 nC mean on a SOT-23
Power dissipation is capped at 360 mW at ambient temperature, which is typical for a SOT-23 package without a heatsink. Input capacitance of 41 pF at 25 V drain-source keeps switching losses minimal at moderate frequencies.
The SOT-23 footprint is standard and easy to hand-solder or reflow, making it field-serviceable with a basic iron.