TUSB1142: Rx GPS band noise

Roy Chou1

Genius 16080 points

Part Number: TUSB1142

Tool/software:

Hi Team,

Currently, we met the issue on the GPS band. (1.56G~1.58GHz) Below is our work around.

Before

After

But I am not sure if it will affect the SI if we place the HF cap on the USB3 line. Do you have any other suggestions?

Regards,

Roy

6 months ago

0 Vishesh Pithadiya 6 months ago

TI__Mastermind 38385 points

Hi Roy,

We haven't needed to do this test for our part in the past, so I'm not familiar with the full setup or results. From what I see it looks like a noise injection test, is that correct?

Regarding the capacitor RX2+ and RX2-, this will negatively impact signal integrity along side the caps C7022, C7023, C7028, and C7029. The best way to test the impacts of these caps this would be to run RX JTOL compliance. Additional functional testing will also be helpful (USB SS detection and file transferring)

0 Vishesh Pithadiya 6 months ago in reply to Vishesh Pithadiya

TI__Mastermind 38385 points

Hi,

I'm closing this thread due to inactivity

0 Roy Chou1 6 months ago in reply to Vishesh Pithadiya

TI__Genius 16080 points

Hi Vishesh,

The test is RE test instead of noise injection. For side effect, I only know the SI should be affected.

Roy

0 Vishesh Pithadiya 5 months ago in reply to Roy Chou1

TI__Mastermind 38385 points

Hi Roy,

Yes adding the C7021 and C7014 will impact the signal integrity as this will slow down the edges of the signal. The only way to confirm if this is a valid solution is to run an RX JTOL test to make sure the system is still USB compliant.

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TUSB1142: Rx GPS band noise