MC33816 over_temp fault

[rmaier]

Hello,

I am working on a new application with the MC33816. The injectors are not firing. I see that I have an over_temp fault in the Driver_config register. When I measure the IC with a thermal camera, it appears to only be 40 deg C. Is it possible I may have caused damage to the IC somehow? Would you recommend replacing the IC, or check elsewhere first?

Thanks,

Robert

[rmaier]

I have replaced the IC, and the same issue occurs. We have a previous rev PCB that worked fine. There are two principal changes made regarding the MC33816. The VCCP is now supplied with an external regulator. Also, caps were added to VCC2P5. I have image below.

I can confirm VCCP is 7.1V.

Some other changes are in reducing noise in VBOOST circuit, which appears to be working just fine.

[guoweisun]

If you change VCCP from LDO into  external power supply, does this issue disappear?

[guoweisun]

You can change new one to test again,if still has issue please share with your schematic.

[rmaier]

I noticed that the boost converter switching FET is being switched at 550 kHz (roughly). The data sheet calls out a frequency range of 100-300 kHz. How is this frequency defined? Is this perhaps related?

[guoweisun]

Yes the Boost switch frequency is abnormal,what's the output of boost?