Dual N-channel logic-level switch in a flat-lead package
The SI5908DC-T1-E3: The SI5908DC-T1-: The Vishay SI5908DC-T1- is a dual N-channel MOSFET from the TrenchFET series, built for low-voltage rail switching where a logic-level gate threshold is needed. Each channel is rated for 20 V drain-source and 4.4 A continuous drain current at 25 °C, with a maximum on-resistance of 40 mOhm at 4.5 V gate drive. The dual-channel configuration saves board area compared to two single MOSFETs when you need independent load switching or a half-bridge leg.
Total gate charge is 7.5 nC at 4.5 V. That is low enough that a microcontroller GPIO can drive the gate directly at tens of kHz without excessive switching loss.
The 1.1 W maximum power dissipation in the ChipFET package is the thermal constraint — derate for high ambient or limited copper area on the PCB.