200 V N-channel in a DirectFET MZ can
The IRF6785MTRPBF is an Infineon HEXFET N-channel MOSFET rated for a drain-to-source voltage of 200 V and a continuous drain current of 3.4 A at 25°C ambient (Ta) or 19 A at case temperature (Tc). It comes in the DirectFET Isometric MZ package — a low-profile, surface-mount can with a solderable backside that doubles as a thermal pad.
On-resistance and gate drive — what the numbers mean
Rds(on) is 100 mOhm maximum at 4.2 A drain current with 10 V gate drive. That 10 V drive voltage is the recommended gate voltage for minimum on-resistance; driving at lower Vgs (down to threshold) will increase Rds(on) significantly. Gate charge totals 36 nC at 10 V — a moderate figure that a standard MOSFET driver can handle without excessive switching loss at frequencies up to a few hundred kHz. Input capacitance Ciss is 1500 pF typical at 25 V drain-source. This capacitance, combined with the gate charge, sets the switching speed and driver current requirement. For a 100 kHz hard-switched converter, the 36 nC gate charge translates to about 3.6 mA average gate drive current — well within the capability of a typical 1 A driver.
Thermal reality — Ta vs Tc ratings
The 3.4 A continuous drain rating at 25°C ambient (Ta) assumes free-air convection on a standard FR4 board with no heatsink — that is the practical limit for a board-level design. The 19 A rating at case temperature (Tc) assumes the DirectFET backside is soldered to a large copper pad or heatsink that keeps the case at 25°C. Power dissipation is 2.8 W at Ta and 57 W at Tc, reflecting the thermal resistance difference.
Lifecycle and sourcing
It is ROHS3 compliant.