P-channel load switch for 20 V rails
The Infineon BSS215PH6327XTSA1 is a P-Channel enhancement-mode MOSFET from the OptiMOS™ family, rated for a maximum drain-to-source voltage of 20 V and a continuous drain current of 1.5 A at 25°C ambient. It comes in a standard SOT-23-3 surface-mount package, identified as the PG-SOT23 supplier device package. This part is designed for low-voltage load switching, battery protection, and power management in space-constrained designs where a P-channel device simplifies the gate drive by switching the high side without a charge pump.
On-resistance and gate drive — what 150 mOhm at 4.5 V means
The maximum on-resistance is 150 mOhm when the gate is driven to 4.5 V with 1.5 A of drain current. That 4.5 V drive level is typical of a 5 V logic output or a 3.3 V system with a level shifter — the part also specifies drive down to 2.5 V for minimum Rds(on), though the on-resistance will be higher at that lower gate voltage. For a 1 A load at 4.5 V drive, conduction loss is roughly 150 mW, which stays within the 500 mW power dissipation limit at 25°C ambient. The gate charge is only 3.6 nC at 4.5 V, so a GPIO pin can switch it directly without a dedicated gate driver.
The 150°C maximum junction temperature gives headroom for self-heating in a high-ambient application, but the SOT-23-3 package limits total power dissipation to 500 mW at 25°C ambient, with derating above that temperature.