CDCE62005: What is this circuitry? and how to deal with LVPECL

Ryan Meruvia

Part Number: CDCE62005

I wanted to ask what this circuitry does exactly. We are making a PCB with this PLL, however, we are not using USB to execute the SPI commands so we wont have the TUSB3210 IC and thus wont have the Y0_150_TERM input. What should we do in this case? Also, is there any specific circuitry we need to deal with LVPECL? Or can we just take the output signal and pass it through a capacitor to the SMA connector? Thank you!

over 5 years ago

0 Shawn Han over 5 years ago

TI__Genius 9920 points

Hi Ryan,
That's for 150 Ohm Ouput Termination controlling. If CDCE62005 using LVPECL type, each line need a 150 Ohm bias resistor to GND; If CDCE62005 using other output type, the bias resistors are no useful, and should be floated.
In your case, if LVPECL type is fixed, then 150 Ohm resistors also could be connected to GND directly (no necessary to design in programming mode as EVM showed). Then AC caps and SMA connectors.

Refer to below application notes ""AC-Coupling Between Differential LVPECL, LVDS, HSTL,and CML""
www.ti.com/.../scaa059c.pdf

Regards,
Shawn

0 Ryan Meruvia over 5 years ago in reply to Shawn Han

Prodigy 60 points

Hello Shawn,

That's what I thought it was for. Thank you, your reply helped us immensely!

Regards,

Ryan

0 Dean Banerjee over 5 years ago in reply to Ryan Meruvia

TI__Mastermind 27661 points

Ryan

Glad to hear we were able t o resovle this. I am going to close the thread.

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CDCE62005: What is this circuitry? and how to deal with LVPECL