DS90UH928Q-Q1: PDB shutdown on chip regulator?

Shinji Tsuji

Genius 14139 points

Part Number: DS90UH928Q-Q1

Hi team,

1. I would like to know if on chip regulator of DS90UH928-Q1 is ON/OFF by PDB pin?

I think there is a bypass pin for CAP I2S/LV25/LV12/R12/P12/L12.

Are these pins all be OFF when PDB=Low?

2. Is there over current protection on these on chip regulator?

I concern if inrush current due to too much bypass capacitor causes the current limit to prevent power on.

regards,

over 4 years ago

0 Logan Cummins over 4 years ago

TI__Guru 66820 points

Hi Shinji,

If the recommended amount of capacitance is used off of these rails and VDD rails are powered on according to power sequencing table, there shouldn't be any issues with inrush currents, current limiting, etc.

Regards,

Logan

0 Shinji Tsuji over 4 years ago in reply to Logan Cummins

TI__Genius 14139 points

Hi Logan,

I would like to have a circuit level evidence of why there should be no issue.

I plan to use following 4.7uF MLCC for each CAPxxx. Does it meet the requirement?

JMK212B7475KGHT(Taiyo Yuden)

regards,

0 Logan Cummins over 4 years ago in reply to Shinji Tsuji

TI__Guru 66820 points

Hi Shinji,

Shinji Tsuji said:
I would like to have a circuit level evidence of why there should be no issue.

I'm not sure I'm understanding your question/concern.

Our datasheet recommends to use 4.7uF capacitors on all of the highlighted pins below. As such, there are no issues given the start-up sequencing requirements are met (PDB enabled after VDDIO and VDD33 are stable).

Regards,

Logan

0 Shinji Tsuji over 4 years ago in reply to Logan Cummins

TI__Genius 14139 points

Hi Logan,

I am reviewing my schematic and would like to make sure the components below are suitable for this bypass cap or not.

JMK212B7475KGHT

Any 4.7uF MLCC is OK? Is there ESR requirement?

regards.

+1 Logan Cummins over 4 years ago in reply to Shinji Tsuji

TI__Guru 66820 points

Hi Shinji,

That capacitor is suitable. It is comparable to ESR of capacitor used in the EVM.

Regards,

Logan

Interface

Interface forum

DS90UH928Q-Q1: PDB shutdown on chip regulator?