Gate-drive budget: 4.5 V logic-level threshold
The IRLR8743TRPBF: Total gate charge is 59 nC at 4.5 V. A driver that swings to at least 4.5 V is needed. Input capacitance Ciss is 4880 pF at 15 V drain-source.
Thermal reality: 135 W in the DPAK tab
Maximum power dissipation is 135 W at case temperature — that figure assumes the tab is soldered to a large copper island with good thermal vias to an inner plane. In a real 1-oz two-layer board, the continuous current is derated well below 160 A; the package thermal resistance dominates. The DPAK (TO-252) footprint has a single exposed tab on the drain. The tab must be connected to the drain net with a copper area and thermal-via array for the 175°C junction rating.
ROHS3 compliant, so the part passes current EU exemption rules for lead-free assembly.