DS90UB954-Q1: refclk check

peiyq

Part Number: DS90UB954-Q1

Hi TI,

We are using DS90UB954-Q1 , we want to using system clock as refclk,could you check attachment can match 954 criteria of refclk？

thanks

peiyuanqing

over 6 years ago

0 Casey McCrea over 6 years ago

TI__Guru** 103215 points

Hello,

The REFCLK input must match the input specifications described in Table 3 of the datasheet. The single scope video from above is not enough to properly characterize the signal. Please perform measurements on all listed items in the table to make the determination.

Best Regards,
Casey

0 peiyq over 6 years ago in reply to Casey McCrea

Expert 1400 points

Hi Casey，
here is test result ，could you check if it can meet ref clock requirement？
Thanks
pei yuanqing

0 peiyq over 6 years ago in reply to peiyq

Expert 1400 points

2ma.pdf

0 Casey McCrea over 6 years ago in reply to peiyq

TI__Guru** 103215 points

Hello,

The rise time is exceeding the max spec in the 954 REFCLK requirements table. Also, this report does not show a critical parameter which is the clock jitter. The results are taken from one sample only. Please characterize the clock jitter to ensure it is lower than the max spec of 200ps p-p

Best Regards,
Casey

0 peiyq over 6 years ago in reply to Casey McCrea

Expert 1400 points

0 peiyq over 6 years ago in reply to peiyq

Expert 1400 points

Hi Casey，
we test it again，could you check if jitter is in spec?
thannks
pei yuanqing

0 Casey McCrea over 6 years ago in reply to peiyq

TI__Guru** 103215 points

Again, going by the scope shot the average/max jitter is above the limit. The measurement is showing ~400ps p-p jitter mean value which exceeds the datasheet limit.

Best Regards,

Casey

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DS90UB954-Q1: refclk check