DS90UB926Q-Q1: Power-Up Sequence Violation of VDDIO & VDD33

Jingyuan Zhao1

Part Number: DS90UB926Q-Q1

Dear team,

My customer is designing automotive clusters with DS90UB926Q-Q1. The project has gone to production until they realize the power up sequence requirement of 100us between VDDIO & VDD33 as stated in datasheet. The hardware has been fixed with VDDIO and VDD33 tied together.

So we are evaluating the risks of power up sequence violation, and my customer would like to know:

1. What's the potential problems of this power up sequence violation may cause?

2. Is there a software solution can fix the problem (e.g. like SW reset) since it has already been in production?

Thanks a lot!

BR,

Charles

over 4 years ago

0 Charley Cai over 4 years ago

TI__Genius 12866 points

Hi Charles,

Please refer to the datasheet again. If they have tied VDDIO and VDD33 together, they can ramp them at the same time.

Best Regards,

Charley Cai

0 Jingyuan Zhao1 over 4 years ago in reply to Charley Cai

TI__Prodigy 440 points

Hi Charley ,

Thanks for your reply!

But I still find it a bit confusing. If it is ok to power up VDDIO and VDD33 at the same time, why VDDIO must ramp 100us ahead VDDIO when powered separately?

BR,

Charles

0 Charley Cai over 4 years ago in reply to Jingyuan Zhao1

TI__Genius 12866 points

Hi Charles,

When powered separately, the VDDIO may be at different voltage (1.8V) and may have different characteristic. We want to ensure that VDDIO is in steady state before VDD33 in such cases.

Best Regards,

Charley Cai

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DS90UB926Q-Q1: Power-Up Sequence Violation of VDDIO & VDD33