NexFET N-channel for low-voltage power stages
The Texas Instruments CSD16401Q5 is a 25 V N-channel NexFET MOSFET in an 8-VSON-CLIP (5x6) package, rated for 38 A continuous drain at 25°C ambient and 100 A at case temperature.
Gate charge and switching speed
Total gate charge is 29 nC at 4.5 V drive, which keeps the gate-drive energy per cycle low. In a 500 kHz converter the average gate-drive current is about 14.5 mA — well within the capability of a standard MOSFET driver IC. The input capacitance of 4100 pF at 12.5 V drain-source means the driver sees a moderate capacitive load; rise and fall times are determined by the driver's source/sink current and the external gate resistor.
Thermal and package reality
The 3.1 W power dissipation at 25°C ambient (Ta) is the limit when the device is mounted on a standard FR-4 board with minimal copper. The 100 A drain current at case temperature (Tc) assumes the bottom-side exposed pad is soldered to a large copper pour and the junction stays below 150°C. The VSON-CLIP package uses a copper clip over the die instead of bond wires, which reduces package resistance and improves heat spreading into the PCB — a real advantage over a conventional DFN in the same footprint.