TUSB551: About method to improve eye pattern

Andrew Xiong

Part Number: TUSB551

Hi,

My customer H3C uses the TUSB551 in their system. Now they tested the eye pattern at Tx and the pattern couldn't reach their requirement.

Now the configuration is: EQ is pulled to ground, OS and DE are floating like the figure 12 configuration on datasheet. Customer wants to know what they can do for the configuration to get better eye pattern. Could you please share any thoughts and comments about this?

Thanks,

Andrew

over 4 years ago

0 Andrew Xiong over 4 years ago

TI__Expert 5470 points

The eye pattern is as attached. The eye height is less than customer's request.

0 Malik Barton57 over 4 years ago in reply to Andrew Xiong

TI__Guru 64326 points

Hi,

Where is this TUSB551 located on the board? Customer could try pulling DE high to get better TX eye result but the eye listed above is pretty good. What is the customer expectation here?

0 Miranda Gu over 4 years ago in reply to Malik Barton57

TI__Genius 16632 points

Hi Malik,

Thanks for your reply. p.s. I co-work with Andrew on this case.

Customer requirement is ±100mV, while current eye height is close to the limit ±100mV.

I will let customer try to pull DE high to see if there's any improvement, thank you.

0 Malik Barton57 over 4 years ago in reply to Miranda Gu

TI__Guru 64326 points

Hi Miranda,

Customer may also need to consider improvements to the layout to help reduce jitter. This can also help increase measured eye height and meet requirement.

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TUSB551: About method to improve eye pattern