SLVSEC9C September 2019 – February 2020 DRV8904-Q1 , DRV8906-Q1 , DRV8908-Q1 , DRV8910-Q1 , DRV8912-Q1
PRODUCTION DATA.
The device junction temperature (TJ) is calculated by the power dissipation and the thermal parameters (Junction-to-Ambient Thermal Resistance (RθJA)) for the particular PCB. For an ambient temperature of TA and total power dissipation (PTOT), the junction temperature (TJ) is calculated as shown in Equation 18.
Considering a 4-layer PCB, with copper thickness as 2-oz and copper-pad area as 16-cm2, the junction-to-ambient thermal resistance (RθJA) can be taken from Figure 154 as 22°C/W.
By putting the value of total power dissipation (PTOT) from Equation 17 in Equation 18 and taking ambient temperature (TA) as 25°C, the junction temperature is calculated as shown in Equation 19.
Hence, the power dissipation of 2.3076-W in the DRV89XX-Q1 device causes the junction temperature (TJ) to increase to 75.77°C. This junction temperature has a margin of 74.23°C before hitting the thermal shutdown limit.