We have received this inquiry from our customer,
We're having some problems with the DRV8332 (or not necessarily problems, but might lack some understanding, so hope you might be able to assist). We've been testing the DRV8332 (HSSOP) without a heatsink, and we're struggling to understand thermal data. See attached an image captured with our thermal imager. Notice the ~30°C difference between the thermal pad and plastic body. Running to motor up and down we've managed to get the plastic body up to 90°C, with the thermal pad still at ~20°C. This seems unusual. Why is the thermal pad not heating above ambient (room is roughly 20°C with no airflow) when the device is clearly generating significant heat. It almost seems like the thermal pad is not connected to the substrate? We've repeated this test on multiple devices, all behaving similarly.
We measured the temperatures using thermocouples as well to verify the imager data. For this particular instance the thermocouple mounted to the thermal pad was around 20deg and the one on the plastic case around 45deg. The thermal imager (as per the photo) measured around 20deg and 50deg for the pad and plastic case.