ZHCSIN3A August 2018 – June 2019 DRV8350 , DRV8350R , DRV8353 , DRV8353R
PRODUCTION DATA.
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 dual supply operation, first the internal power dissipation must be calculated. The internal power dissipation has four primary components:
The value of PVCP and PVGLS can be approximated by referring to External MOSFET Support to first determine IVCP and IVGLS and then referring to Equation 45 and Equation 46.
The value of PVM can be calculated by referring to the datasheet parameter for IVM current and Equation 47.
where
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 50.
Lastly, the device junction temperature can be estimate by referring to the Thermal Information and Equation 51.
Note that the information in the 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.