The Infineon IRF9540NSTRRPBF is a P-Channel enhancement-mode MOSFET from the HEXFET® series, built with planar stripe technology. The D2PAK (TO-263) surface-mount package suits medium-power boards with decent copper area for heat spreading.
The 100 V Vdss rating gives comfortable headroom for 48 V bus rails and plenty of margin on 12 V or 24 V systems. At 23 A continuous drain current, this part can handle moderate motor loads or power distribution switches, though the 3.1 W power dissipation at ambient (Ta) means you need the case heatsinking to reach the 110 W Tc limit. Gate charge of 110 nC at 10 V is moderate — a standard gate driver or even a GPIO through a resistor can switch it at a few tens of kHz without excessive drive loss.
Sourcing this part now goes through independent distribution — surplus inventory, last-time-buy stockpiles, or broker channels. If you need a guaranteed long-term supply, consider qualifying a pin-compatible P-channel alternative from the same or a different vendor.