Hi,

I have some questions about XTAL frequency specification for ADV devices.

ADV devices have XTAL frequency specification on the datasheets.

For example, ADV748x datasheet says as follows:

Please let me ask a question about the "Frequency Stability" plus-minus 50ppm.

Question:

Is this required specification for only the XTAL IC?

(We have to keep the plus-minus 50ppm for only the XTAL IC?)

Or

Is this required specification for the XTAL IC and the related circuit (including Rdump and C etc.)?

(We have to keep the plus-minus 50ppm for the XTAL IC and including the error/variation of the related circuit (including Rdump and C etc.)?)

Which is correct?

Background:

My customer uses ADV devices (ADV7182A, ADV7282A-M, ADV7611 and ADV7480, etc.)

He uses a XTAL IC keeping the "Frequency Stability" plus-minus 50ppm on the datasheets.

But when considering the related circuit (including Rdump and C etc.), he says the plus-minus 50ppm can not be kept.

The error/variation of the related circuit is plus-minus 25ppm in room temperature, he says.

So we ask these questions.

If the plus-minus 50ppm is required specification for only the XTAL IC, could you tell me the needed "Frequency Stability" for the related circuit (including Rdump and C etc.)?

Thank you!

Best regards.

Tamu