DS90UB925Q-Q1: Detailed Design Procedure query

Youhei Miyaoka

Expert 3995 points

Part Number: DS90UB925Q-Q1

Tool/software:

Hi team,

My customer want to confirm this datasheet meaning,.

They have a guess, that minimum (6) 4.7uF , are below(C4-C9), but not sure ,

or does it mean minimum (6) are needed at VDD33 and VDDIO?and also where are these 1uF caps required?

Regards,

Youhei MIYAOKA

4 months ago

0 Fadi Abdulhameed 4 months ago

TI__Mastermind 29575 points

Hello Youhei,

I will review and get back to you tomorrow, thanks!

- Fadi A.

0 Youhei Miyaoka 4 months ago in reply to Fadi Abdulhameed

TI__Expert 3995 points

Hello Fadi,

Thanks for your support. This question comes from US engineer and checking this thread. Can you answer early in the day please?

Regards,

Youhei

0 Fadi Abdulhameed 4 months ago in reply to Youhei Miyaoka

TI__Mastermind 29575 points

Hello Youhei,

Correct, that minimum (6) 4.7uF , are below(C4-C9) - Those are correct.

The (2) 1 uf Caps are not required. You can use these at the main power supply input for additional filtering but it's not required per our device spec.

For legacy devices, it's recommended to follow the EVM design schematic as well as the datasheet typical application diagram.

925_EVM.pdf

- Fadi A.

0 Youhei Miyaoka 4 months ago in reply to Fadi Abdulhameed

TI__Expert 3995 points

Hi Fadi,

But then you recommended to also follow the EVM schematic, where EVM schematic shows 22uF placed on both VDD33 and VDDIO which is not per device spec or typical application diagram , could you please check, if 22uF are not required they will not place them.

Regards,

Youhei

0 Fadi Abdulhameed 4 months ago in reply to Youhei Miyaoka

TI__Mastermind 29575 points

Hello Youhei,

The typical application diagram shows the minimum requirements for this device's application. Anything beyond those recommended components are ok to use but it's not required.

- Fadi A.

0 Youhei Miyaoka 3 months ago in reply to Fadi Abdulhameed

TI__Expert 3995 points

Hi Fadi,

Thank you. One more query from the customer;

When it is said 4.7uF is required at VDD33, is it due IC design? Or is it considered per worst case scenario of possible data transfer on IO lines?

Regards,

Youhei

0 Fadi Abdulhameed 3 months ago in reply to Youhei Miyaoka

TI__Mastermind 29575 points

Hello Youhei,

This is for worse case across PVT (power voltage the temp changes) per IC design and validation recommendation.

- Fadi A.

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DS90UB925Q-Q1: Detailed Design Procedure query