DS90UB926Q-Q1: Schematic review

Kygo Cheng

Part Number: DS90UB926Q-Q1

Hi team

There is a good new that we DIN DS90UB926Q-Q1 !

1.The attachment is for the DS90UB926Q schematic and PCB Layout, please help to review it!

2.What is means of below orange line means? The EVB also use SMD Pads and the track also > 1.5W, please help to confirm. THX

FPD-LINK DS90UB926Q Schmatic.pdf

TI_LAYOUT VIEW.pdf

over 3 years ago

0 Casey McCrea over 3 years ago

TI__Guru** 103215 points

Kygo,

Here is the reviewed schematic:

Reviewed FPD-LINK DS90UB926Q Schmatic.pdf

I will work on the layout review next

Best Regards,

Casey

0 Kygo Cheng over 3 years ago in reply to Casey McCrea

TI__Expert 6830 points

Hi Casey

Thank you for the support!

There are some design question for 926 that customers would like to discuss with you!
Is it convenient to make an appointment with you this week? THX

0 Casey McCrea over 3 years ago in reply to Kygo Cheng

TI__Guru** 103215 points

Kygo,

Are the questions possible to discuss over this same E2E thread?

Best Regards,

Casey

0 Kygo Cheng over 3 years ago in reply to Casey McCrea

TI__Expert 6830 points

Hi Casey

Yes!

Discuss on the E2E first!
If time is tight, customers will want to directly hold a meeting to discuss, then we can set the meeting,THX

0 Casey McCrea over 3 years ago in reply to Kygo Cheng

TI__Guru** 103215 points

Hey Kygo,

Do you have the questions from the customer to share here?

Best Regards,

Casey

0 Casey McCrea over 3 years ago in reply to Casey McCrea

TI__Guru** 103215 points

Kygo,

Please see attached for layout feedback. One thing I noticed is that the FPD routing is quite long - this is much longer than I would usually recommend. Please ensure that the customer is aware that based on their stackup and materials selection this routing may incur quite a large insertion loss and eat into cable budget

Reviewed_TI_LAYOUT VIEW.pdf

Best Regards,

Casey

0 Kygo Cheng over 3 years ago in reply to Casey McCrea

TI__Expert 6830 points

Hi Casey

Thank you for the support!

I will continue to discuss with RD, and will let you know after confirming the customer's questions.

0 Kygo Cheng over 3 years ago in reply to Kygo Cheng

TI__Expert 6830 points

Hi Casey

Could you reply belows two question? THX

Can we follow the right side of the tightly coupled for the high-speed differential signal trace design?

The is the means for the “ This rule does not apply where SMD pads on high-speed differential signals are voided.”Since we are use the SMD pads on high-speed differential signals, does that means the high-speed differential signals no need have routed with ground at least 1.5W?

0 Casey McCrea over 3 years ago in reply to Kygo Cheng

TI__Guru** 103215 points

Hello Kygo,

#1: Yes, this would be the correct method for 926 FPD routing

#2: I'm not sure I understand the question here but the goal of the datasheet statement is to ensure that the GND plane under the high speed traces and near to the edge of the high speed traces remains continuous to ensure stable 100ohm differential impedance. The exception is if the GND on the reference plane is intentionally voided under any component pads where the trace geometry widens since the goal of that void would be to counteract the parasitic capacitance and return the impedance back to 100 ohm

Best Regards,

Casey

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DS90UB926Q-Q1: Schematic review