Other Parts Discussed in Thread: CDCM6208
On the TICSPro software, there is no option to specify LVPECL as the input reference type. I see the circuit in figure 18 of the CDCM6208 datasheet, but which option should be specified in software?
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On the TICSPro software, there is no option to specify LVPECL as the input reference type. I see the circuit in figure 18 of the CDCM6208 datasheet, but which option should be specified in software?
Matthew,
In the datasheet, it lists later on (page 29) that the universal input supports these input types: (LVDS, CML or LVCMOS) - at first glace it looks as if this part does not actually support LVPECL input, despite what the first page of the datasheet says. There is not a mention of LVPECL in the differential input characteristics table either.
However, on page 23 of the datasheet, there is a diagram for the LVPECL input configuration:
This looks nearly identical to the CML configuration, except the pullup voltage is different:
I believe that you may be able to use the CML input selection for LVPECL - I will try this on the bench and see if this is successful, and let you know by tomorrow.
Thanks,
Kadeem
Matthew,
Unfortunately, it does not look like this device supports an LVPECL input (confirmed with the EVM User's Guide as well).
Thanks,
Kadeem
So I take it that your bench testing with LVPECL inputs in the CML configuration were unsuccessful? Did you also try biasing to Vcc-2?
Thank you for the assistance.
Matthew,
I have an update - I had neglected to increase the VDD_PRI appropriately. With this adjustment, plus the biasing to Vcc - 2, LVPECL is supported for the input of this device.
Thanks,
Kadeem
Matthew,
My pleasure. Please do not hesitate to reach out if any further questions arise.
Thanks,
Kadeem