SLVSFV6B August 2022 – October 2023 DRV8962
PRODUCTION DATA
The estimated junction temperature will be: TJ = TA + (PTOT x θJA)
The junction-to-ambient thermal resistance θJA is 22.2 °C/W for the DDW package on a JEDEC standard PCB, and close to 5 °C/W for the DDV package if a suitable heat sink is used.
Therfore, the first estimate of the junction temperature is -
TJ = TA + (PTOT x θJA) = 25 + (2.552 x 22.2) = 81.7 °C
For more accurate calculation, consider the dependency of on-resistance of FETs with device junction temperature shown in the Typical Operating Characteristics section.
For example,
At 81.7 °C junction temperature, the on-resistance will likely increase by a factor of 1.3 compared to the on-resistance at 25 °C.
The initial estimate of conduction loss (loss due to RDS(ON)) for each half-bridge was 0.477 W.
New estimate of conduction loss will therefore be 0.477 W x 1.3 = 0.62 W.
New estimate of the total power loss will accordingly be 3.124 W.
New estimate of junction temperature for the DDW package will be 94.4 °C.
Further iterations are unlikely to increase the junction temperature estimate by significant amount.