SLVSDY6A August 2018 – June 2019 DRV8350 , DRV8350R , DRV8353 , DRV8353R
Design care must be taken to make sure that the thermal ratings of the DRV835x are not violated during normal operation of the device. The is especially critical in higher voltage and higher ambient operation applications where power dissipation or the device ambient temperature are increased.
To determine the temperature of the device in single supply operation, first the power internal power dissipation must be calculated. The internal power dissipation has four primary components:
The values of PVCP and PVGLS can be approximated by referring to External MOSFET Support to first determine IVCP and IVGLS and then referring to Equation 26 and Equation 27.
The value of PVM can be calculated by referring to the data sheet parameter for IVM current and Equation 28.
The value of PBUCK can be calculated with the buck output voltage (VVCC), buck output current (IVCC), and by referring to the typical characteristic curve for efficiency (η) in the LM5008A data sheet.
The total power dissipation is then calculated by summing the four components as shown in Equation 31.
Lastly, the device junction temperature can be estimate by referring to Thermal Information and Equation 32.
The information in Thermal Information is based off of a standardized test metric for package and PCB thermal dissipation. The actual values may vary based on the actual PCB design used in the application.