20 V P-channel FET for low-side switching
The PMN40UPEA115 is a P-channel enhancement-mode MOSFET from Nexperia in a 6-pin SC-74 (SOT-457) surface-mount package. It is rated for a drain-source voltage of 20 V and a continuous drain current of 4.7 A at 25 °C ambient.
On-resistance and gate drive
The maximum on-resistance is 43 mOhm at a gate-source voltage of 4.5 V with 3 A drain current. The drive voltage range spans 1.8 V to 4.5 V, so the FET can be fully enhanced by a 3.3 V logic-level gate signal, but the lowest Rds(on) is achieved at 4.5 V. Gate charge totals 23 nC at 4.5 V, and input capacitance is 1820 pF at 10 V drain-source. These numbers are moderate — a GPIO pin or a small gate-driver IC can switch it at a few hundred kHz without excessive drive current.
Thermal limits and package reality
Power dissipation is rated 500 mW at ambient temperature and 8.33 W at the case. The SC-74 package has no exposed pad, so in still air the 4.7 A continuous rating is only achievable with generous copper area on the PCB — expect derating above 70 °C ambient.