100 V P-channel — the high-side switch for 48 V rails
The Infineon BSP321PL6327 is a P-channel SIPMOS MOSFET with a 100 V drain-source breakdown and a continuous drain current rating of 980 mA at 25°C case temperature. P-channel at this voltage is the part you reach for when you want a simple high-side switch without a charge pump — the gate just needs to be pulled below the source to turn on.
Gate drive and switching — what the numbers mean at the bench
The gate threshold voltage is specified at 4 V maximum with 380 µA drain current — that 4 V ceiling means a 5 V logic signal from a microcontroller or gate driver will turn this FET fully on, but a 3.3 V logic rail is marginal and may not guarantee the full Rds(on). Total gate charge is 12 nC at 10 V, so a 100 mA gate driver can switch it in about 120 ns — fast enough for a 100 kHz SMPS, but the 319 pF input capacitance at 25 V drain-source means the driver sees a capacitive load that rings if the layout is sloppy.
Package and thermal — the copper pad is the heatsink
The PG-SOT223-4-21 package is a surface-mount power package with the tab as the drain. The 1.8 W maximum power dissipation at 25°C ambient assumes a standard FR-4 board with minimum copper — if you need to push the full 980 mA continuous at high ambient, the tab needs a generous copper pour and vias to a ground plane to keep the junction below 150°C.
Lifecycle and sourcing — still in production
ROHS3 compliant, no exemptions expiring.