DS90UB954-Q1: About amplitude of CMLOUT

Tomoaki Yoshida91

Part Number: DS90UB954-Q1

Hi team,

I have a question for CMLOUT.

Our customer will evaluate CMLOUT of their system.

At that time, they will monitor the eye opening and amplitude, but the amplitude was not mentioned in the CMLOUT section of the data sheet.

It is written that minimum Ew is 0.45UI.

Can I think that the amplitude specification is equivalent to Vid in the data sheet?

Best regards,

Tomoaki Yoshida

over 7 years ago

0 Palaniappan Manickam over 7 years ago

TI__Genius 10475 points

Yoshida-san,
The eye height is not a critical parameter. Only eye width is critical due to the limiting amplifier gain in the RX.

0 Tomoaki Yoshida91 over 7 years ago in reply to Palaniappan Manickam

Genius 5255 points

Hi Palaniappan-san,

Thank you for your support.

I don't understand the reason why the eye height is not a critical.

I am planning to use CMLOUT to monitor whether the input amplitude of RX can satisfy communication.

Is there no correlation in height between the actual RX input and CMLOUT?

Or does it mean that there is no need to monitor because the amplification is sufficient for communication internally?

Best regards,

Tomoaki Yoshida

0 Palaniappan Manickam over 7 years ago in reply to Tomoaki Yoshida91

TI__Genius 10475 points

Hello,
The eye height is not critical because of the limiting amplifier gain in the RX. So you only need to monitor the CMLOUT eye width and make sure it meets the requirement.

Interface

Interface forum

DS90UB954-Q1: About amplitude of CMLOUT