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FRoth's avatar
FRoth
Icon for New Contributor rankNew Contributor
6 years ago

Arria 10 HSSI receiver PHY CDR reference clock related questions

The Arria 10 Device Datasheet / Arria 10 Native PHY Datasheet are not very clear on the HSSI RX reference clock requirements. It would help us greatly if you could answer the following HSSI reference...
CheepinC_altera's avatar
CheepinC_altera
Icon for Regular Contributor rankRegular Contributor
6 years ago

Hi,

As I understand it, you have some inquiries related to the CDR refclk. I have looked through the device datasheet and you are right, there is no specific specs on the CDR refclk. However, generally those supported refclk options in the drop down list of the Native PHY are validated working frequency. In other words, the 50MHz is the minimum value for your specific configuration in Native PHY.

As for the HDMI, if I understand it correctly, it should be related to the HDMI protocol requirement and Engineering has perform specific characterization on this frequency.

As for the jitter requirement for the CDR refclk, you may refer to the following specs in the datasheet:

1. Transmitter REFCLK Phase Noise

2. Transmitter REFCLK Phase Jitter

They are applicable to CDR refclk as well.

Regarding the reconfiguration of the CDR refclk, since the minimum is 50MHz for your configuration, we would not be able to go lower than that. Sorry for the inconvenience.

Please let me know if there is any concern. Thank you.

Best regards,

Chee Pin