DS90UB935-Q1: Schematic design

user5999304

Prodigy 40 points

Part Number: DS90UB935-Q1
Other Parts Discussed in Thread: TIDA-020003

Dears

We have almost finshed the schematic design of this scheme. Could you please help us review the schematic design？

over 3 years ago

0 Casey McCrea over 3 years ago

TI__Guru** 102595 points

Hello,

Did you mean to attach a schematic here? We can help review your schematic, but it is not showing up in this post

Best Regards,

Casey

0 user5999304 over 3 years ago in reply to Casey McCrea

Prodigy 40 points

Dear Casey

Yes，FYIxv_fpdlink_9356_fpc_v0_0301.pdf

0 Casey McCrea over 3 years ago in reply to user5999304

TI__Guru** 102595 points

Hello,

The schematic looks good overall! For the 935 CLKIN, if you do use it for non-synchronous mode, then 50MHz is suggested instead of 25MHz in order to get full rate speed on the FC. If you use 935 in non-synchronous mode with a 25MHz CLKIN, then the forward channel link speed with be 2Gbps instead of 4Gbps. Also on the 936 side I can't see the circuit for how PDB is controlled, but make sure that PDB does not pull high until all the power supplies are stable per the datasheet power sequence.

Best Regards,

Casey

0 user5999304 over 3 years ago in reply to Casey McCrea

Prodigy 40 points

Dear Casey

I can't guarantee the last bit of routing at this point can meet the 50ohm routing requirements ，Cause that a current of more than 200mA is required. What should I do with it?

I have checked the TIDA-020003 Gerber information， I was also confused it.

0 Casey McCrea over 3 years ago in reply to user5999304

TI__Guru** 102595 points

Hello,

How much current is needed on the PoC here? The PoC network itself is only designed to deliver around 250mA of continuous current based on the component selection. If you need to deliver more power the general recommendation is to increase the PoC voltage to keep the current minimal

Best Regards,

Casey

0 user5999304 over 3 years ago

Prodigy 40 points

About 250mA,5mil route width.

0 Casey McCrea over 3 years ago in reply to user5999304

TI__Guru** 102595 points

Hello,

I would suggest suggest sizing your trace to meet 50ohm characteristic impedance based on your stackup and material selection firstly, and then check if there are any concerns from the thermal perspective with the trace sizing. Based on your design, it looks like either the first part or the second part of your trace will not be hitting a target 50 ohm impedance since they are on the same layer and have different widths. 250mA is a relatively small current draw and should not drive an increase in the trace width unless your copper thickness is really low.

Best Regards,

Casey

0 user5999304 over 3 years ago in reply to Casey McCrea

Prodigy 40 points

Got it，

Thank you very much.

Best Regards

0 Aaron Heng over 3 years ago in reply to user5999304

TI__Mastermind 31650 points

Hello,

I will close this thread for now. If you have further questions, please reach out to us again.

Aaron

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DS90UB935-Q1: Schematic design