DS90UB954-Q1: Power up sequencing for DS90UB954

Tiger Wang

Part Number: DS90UB954-Q1

Dear Sir,

I want to use 3.3V for VDDIO, but it seems VDDIO(3.3V) should power up after VDD18, but in my design, VDD18 is the LDO output, the input of LDO is VDDIO(3.3V).

So, The power up sequencing is 3.3V (VDDIO) at first, and then 1.8V later.

Does this sequence of power up meet the following requirements?

Best regards！

over 5 years ago

0 Steven(Shenzhen) Shi over 5 years ago

TI__Mastermind 30515 points

Decai,

You should follow up the d/s design guide. and you can make VDDIO is synced with VDD18 or later than VDD18. thanks.

best regards,

Steven

0 Tiger Wang over 5 years ago in reply to Steven(Shenzhen) Shi

Expert 1535 points

Dear Steven,

Thanks for your comments, you mean VDDIO and VDD18 can be powered up at the same time ?

Best regards.

David

0 Tiger Wang over 5 years ago in reply to Tiger Wang

Expert 1535 points

Dear Steven,

I had read a question which also discuss the power sequence of 954,

e2e.ti.com/.../683039

it seems he suggested VDDIO should be powered first, VDD18 later, can you give me more advice?

Best regards.

David

0 Steven(Shenzhen) Shi over 5 years ago in reply to Tiger Wang

TI__Mastermind 30515 points

Dcai,
You should follow up TI's d/s design. as you mentioned the other case, it is better to remove the glitch if higher voltage VDDIO is powered on firstly. But for the internal digital logic design, it is recommended to power on VDD18 based on d/s page137/138.

but anyway, please make sure that PDB comes high and stable after VDDIO goes high.

best regards,
Steven

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DS90UB954-Q1: Power up sequencing for DS90UB954