DS90CR287: change of frequency

Ralf Goebel

Other Parts Discussed in Thread: DS90CR287

Hello,

I have a question about the input clock of the DS90CR287 Channel Link transmitter:
The datasheet clarifies that the input clock must be valid when powering up the device.
Do I also have to use the PWR_DOWN pin if I want to change the frequency of the transmit clock during operation?
It's no problem for my application if the transmitted data would be invalid for some time, until the PLL locks to the new frequency (TPLLS <= 10ms).

Thanks,
Ralf

over 11 years ago

0 T.K. Chin over 11 years ago

TI__Expert 3175 points

Hi Ralf,

We are looking into this case. Someone from our team will reply shortly.

Regards,

0 Michael Lu (Santa Clara) over 11 years ago

TI__Mastermind 29655 points

Hi Ralif,

According to the datasheet, the PLL locks and generates a recovered clock signal based on the clock signal present at the input upon device power up. Changing the frequency during operation is similar to stopping the clock temporarily, as the original clock signal on the transmit has been interrupted.

I recommend using the PWR_DOWN pin to reset/re-lock the PLL to the new transmit clock frequency.

Thanks,

Michael

0 Ralf Goebel over 11 years ago in reply to Michael Lu (Santa Clara)

Genius 3715 points

Hi Michael,

Thank you for the fast response, this answers my question.

Ralf

Interface

Interface forum

DS90CR287: change of frequency