Since power MOSFETs are integrated on chip, SWIFT devices may be constrained thermally. To check if the package power dissipation rating is exceeded, it is wise to calculate the power dissipation of the SWIFT device under the operating conditions. In the example shown, the input voltage is 24 V, the output voltage is 5 V, and the output current is 3 A. The MOSFET’s worst case Rds(on) is 200mΩ, it has a rise and fall time of 20 nanoseconds, has a quiescent current of 10 mA, and operates at 500 kHz. By using the basic formulas shown, the conduction loss, Pcon, is shown as 430 mW, the switching loss, Psw, is 720 mW, and the quiescent current loss, Pq, is 240 mW. These add up to a total dissipation, Pd, of 1.39 W. Under a worst case condition, according to the datasheet (power dissipation table) for TPS5430, the package can handle 1.5 W with no airflow and ambient temperature of 85 degrees. Therefore, the IC can support 1.39 W of dissipation.