Dear TI Expert,
I'm using DRV8353H for my SRM inverter gate drive application. In that DRV8353 is frequently failing. I suspect that thermal pad is the issue.
I have given thermal pad as recommended but not grounded it. Is it to be grounded(thermal Pad). Other ground Pins i have grounded and it is working fine.
I have attached my circuit here.
Regards,
Kumar
Hello Kumar,
I suspect failing means damage?
We recommend to connect GND to the thermal pad. This illustrated by the pink outline I've given to the Layout Example (Figure 75) given in the datasheet.
There are many reasons, beyond just thermal considerations, for this. Essentially, If the thermal pad is devoted to its own net, then there is a large cut out that goes completely through the PCB (because the thermal vias place directly under the pad should go all the way to the bottom of the board). This cut out requires charge to navigate around the cutout which increase the effective parasitic impedance leading from the V- source of the board or power stage, to the device. This means, sensing circuitry will not have an electrical equivalent node (i.e. 0V at the FET will instantaneously not be 0V at the pin of the device) and damage can occur as well as degraded performance.
We talk about this a little bit in the "Using a GND plane" section of the Best Practices for Board Layout of Motor Drivers app note, which I suggest you review: 
Best,
-Cole
