TUSB1064: TUSB1064 LFPS issue

Gary Teng

Part Number: TUSB1064

Hi all,

My customer ask cypress to reduce their LFPS signal in hub side and retest their board (we don't know the level output from Cypress). But, customer response that our TUSB1064 has different result in LFPS test on the same board:

1. board 1 can pass 5G LFPS test with level 1.1634V

2. board 2 can't pass the test with level 1.2136V

3. board 2 exchange the IC from board 1 and it can pass the test (1.1752V)

Would you please helping to explain why TUSB1064 has different test result in different IC? Or the suggest LFPS test signal level for Hub supplier? Thanks for your response.

Gary Teng

over 6 years ago

0 David (ASIC) Liu over 6 years ago

TI__Guru**** 176371 points

Gary

LFPS min amplitude is 800mV and max amplitude is 1.2V. Please ask Cypress to set the LFPS amplitude to 1V.

Thanks
David

0 Gary Teng over 6 years ago in reply to David (ASIC) Liu

Genius 5830 points

Hi David,
I'll response to customer and will let you know if they have problem in board test. Thanks.

Gary

0 Gary Teng over 6 years ago in reply to Gary Teng

Genius 5830 points

Hi David,
Can customer turn off LFPS amplitude function by I2C setting? Customer has concern about the un-expect gain in test...

0 David (ASIC) Liu over 6 years ago in reply to Gary Teng

TI__Guru**** 176371 points

Gary

By default in I2C, the EQ is already set to 0 for LFPS (LFPS_EQ bit default setting).

Thanks
David

0 Gary Teng over 6 years ago in reply to David (ASIC) Liu

Genius 5830 points

Hi David,

1. Customer has ever test LFPS function and bypass TUSB1064. LFPS signal is amplified thrugh 1064 no matter they set I2C LFPS bit or not.

2. Can you add reference LFPS level on datasheet so we don't need to discuss with hub/host maker if we can't disable LFPS test function?

Thanks.

Gary

0 David (ASIC) Liu over 6 years ago in reply to Gary Teng

TI__Guru**** 176371 points

Gary

I don't fully understand the questions, can Cypress hub change their LFPS amplitude to 1V?

Thanks
David

0 Gary Teng over 6 years ago in reply to David (ASIC) Liu

Genius 5830 points

Hi David,

Yes, Cypress can set LFPS amplitude to 1V, but they want to know

1. Why they have to set to 1V if we have bypass setting?

2. Can we guarantee LFPS signal 1V is ok for TUSB1064?

Thanks for your response.

Gary

0 David (ASIC) Liu over 6 years ago in reply to Gary Teng

TI__Guru**** 176371 points

Gary

We do not have control over LFPS amplitude. LFPS amplitude ranges from 800mV to 1.2V, it is better not to set the LFPS at its min or max level, it is better to set the LFPS amplitude in the middle at 1V.

Thanks
David

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TUSB1064: TUSB1064 LFPS issue