100 V N-channel in a DirectFET can — conduction loss and thermal path
The on-resistance is specified at 62 mOhm maximum when driven with 10 V on the gate and 8.9 A drain current — this is the figure to use for conduction-loss budgeting in a synchronous rectifier or primary-side switch.
At 4.1 A continuous, the I²R conduction loss at 62 mOhm is just over 1 W. The total device dissipation is rated at 2.4 W, so the junction-to-ambient thermal path in the DirectFET package must be managed — the copper area on the drain tab and airflow determine the real thermal limit. The gate threshold is 5 V maximum at 25 µA, so a 10 V gate drive provides ample overdrive for a hard-switched topology.
Junction temperature range and package thermal reality
This matters in a high-ambient enclosure or a motor-drive bay where the MOSFET sits near the heatsink baseplate. The DirectFET package (listed as Bulk in the spec — the part ships in tape-and-reel as the TR suffix indicates) exposes the drain on the top surface for direct heatsinking or PCB copper spreading.
Infineon lists the IRF7665S2TRPBF as Active.