The maximum operating temperature range for the MRF6VP3450HSR5 is -40°C to +150°C.
To optimize the PCB layout, use a thermal pad on the bottom of the package, and connect it to a large copper area on the PCB to dissipate heat. Also, keep the thermal vias as close as possible to the device to reduce thermal resistance.
The recommended land pattern for the MRF6VP3450HSR5 is a non-symmetric land pattern with a larger pad on the thermal pad side to accommodate the thermal pad on the device.
To handle the high voltage on the drain pin, use a voltage regulator or a DC-DC converter to step down the voltage to a level that is within the device's rating. Also, ensure that the PCB layout is designed to minimize voltage stress on the device.
The maximum power dissipation for the MRF6VP3450HSR5 is 100 W. However, this value can be derated based on the operating temperature and other factors.