DRV8305: Having failures appears to be related to over heating.

Part Number: DRV8305

We are using Insta-SPIN motor-ware and the DRV8305 with the TMS320F28027F much like the development board, in fact there are very few hardware changes.  We are experiencing failed units in the field, it is always the DRV8305 that has failed, with the O-Scope I find that all gate-drive signals are missing even when input signals are active and gate-drive is enabled.  SPI is working.

The DRV8305 case temperature can be as hot as 90degC when ambient is 25degC, the failures seem to coincide with ambient temperatures above 30degC.  The DRV8305 measures hotter than the MosFETS.

I'll be honest that I don't understand how the DRV8305 can be so hot, even at ZERO speed the DRV8305 case temp is 70degC.

Gate Drive sink and source currents are set to default 50mA.

PWM freq is 90KHz

We are driving a very low inductance FAN, we command velocities from 0 to 30KRPM:

Any advice appreciated, presently trying different heatsink approaches.