1050 V Vdss in a DPAK — where this MOSFET earns its place
The STD2N105K5 from ST's MDmesh K5 series is an N-channel power MOSFET that squeezes a 1050 V drain-source breakdown voltage into a DPAK surface-mount package. That voltage rating targets offline flyback converters, auxiliary power supplies in industrial drives, and PFC boost stages where the DC bus sits above 400 V. The 1.5 A continuous drain current and 8 Ohm Rds(on) at 10 V gate drive mean it is sized for the low-to-moderate current leg of those rails — think a 10–30 W auxiliary winding, not a multi-kilowatt front end.
Gate drive and switching — 10 nC Qg keeps the driver small
Total gate charge is 10 nC at 10 V Vgs. That is low enough that a simple gate-drive transformer or a small integrated driver IC can switch it into the 100 kHz range without the gate-drive losses dominating the thermal budget.
Thermal and package — DPAK with a 60 W ceiling
Maximum power dissipation is 60 W at the case temperature, and the operating junction range runs from -55°C to 150°C. For a 1.5 A load with 8 Ohm Rds(on), the I²R loss at full current is 18 W; the 60 W ceiling leaves headroom for switching losses and ambient temperature derating.
The base product number is STD2N105, and the K5 suffix identifies the MDmesh K5 series — no official cross-reference or second-source alternate is listed, but the MDmesh K5 family is a current-production line with multiple density options.