TUSB522P: USB 3.0 Specification

Kenji Ohno1

Genius 5095 points

Part Number: TUSB522P

Hi Team,

My customers have questions about TUSB522P.

USB 3.0 Specification Table Table 6-14 contains the parameter VRX - DIFF - PP - POST - EQ.

https://www.usb3.com/whitepapers/USB%203%200%20(11132008)-final.pdf

Does it have the same meaning as V (RX - SIGNAL - DET - DIFF - PP) in section 6.7 on the TUSB522P datasheet?

http://www.ti.com/lit/ds/symlink/tusb522p.pdf

Best Regards,

Kenji

over 6 years ago

0 Brian Zhou over 6 years ago

TI__Guru*** 145620 points

yes, it's same

0 Kenji Ohno1 over 6 years ago in reply to Brian Zhou

Genius 5095 points

Thank you four your answer!

Best Regards,
Kenji

0 Kenji Ohno1 over 6 years ago in reply to Brian Zhou

Genius 5095 points

Brian-san,

I have another question for you.
On the USB 3.0 specification, VRX - DIFF - PP - POST - EQ is stated as 30 mV (min.), But V (RX - SIGNAL - DET - DIFF - PP) is 85 mV (typ) in the TUSB522P datasheet.
Does this mean that the sensitivity of the TUSB522P to the received signal is lower than the USB 3.0 specification?

Best Regards,
Kenji

0 Brian Zhou over 6 years ago in reply to Kenji Ohno1

TI__Guru*** 145620 points

no, hard to compare, one is min spec, one is typical data. but 80mv is higher than 30mv

0 Brian Zhou over 6 years ago in reply to Brian Zhou

TI__Guru*** 145620 points

sorry, or USB expert think these are different, the parameter in the USB spec if for design purposes, it a test point after the equalizer in the receiver (Which isn’t a real test point we can measure).

and the parameter in the 522P datasheet is the squelch limit, a 85mV p-p signal and higher is considered a real signal the device needs to recover, lower than 85mV p-p is considered noise (or Idle).

0 Kenji Ohno1 over 6 years ago in reply to Brian Zhou

Genius 5095 points

Hi Brian-san,

I understand that the specifications are different.
Under the USB 3.0 specification, I understood that the receiver is received as a signal up to 30 mV.
TUSB522P is judged as noise even if 30 mV is input and signal amplification is not done?

Would like to know the reason why the decision threshold is 85 mV (typ.).

I think the role of redriver is to amplify small signals that the receiver does not receive.
I am wondering if the threshold of 85 mV doesn't do its operation.

I appreciate your support.
Best Regards,
Kenji

0 Brian Zhou over 6 years ago in reply to Kenji Ohno1

TI__Guru*** 145620 points

85mv is the value you can measure at RX pin. 30mv is the value inside RX after IO and EQ circuit, you cannot measure it

Interface

Interface forum

TUSB522P: USB 3.0 Specification