We have a couple of custom board designs using the automotive grade RT1176.
In both designs, running our application code, CPU temperature is in the high 50s C. On the EVK, (which is running the commercial grade part) temperatures with the same code are running in the high 30s so there is around a 20C difference between our boards and the EVK. Measurement with an external temperature sensor suggests these temperatures are real.
Our design is very similar to the EVK in terms of QSPI NOR flash, SDRAM and USB but it has a DSI to LVDS bridge plus uses some analogue inputs. All analogues are within range and the device functions correctly.
I have been through our design vs refernce design and all unused pins and power supplies seem to be configured the same. We are using the internal DCDC to supply the processor 1V8 and 1V0; USB 1P8 and MIPI 1P8 are supplied from a separate 1V8 supply so we are within limit for the DCDC convertor. We are running in nominal mode (not overdrive) with CM7 enabled only at 600MHz.
Reducing clock speed brings the temperature down only slightly which suggests there is some leakage or loading somewhere.
Is there any expected difference in thermal behaviour between the automotive and commercial grade parts? Are there any specific areas we should focus on to resolve this temperature discrepancy?
Thanks.
