How to Predict CDCE62002 Loop banwidth

Chris Cotton1

Other Parts Discussed in Thread: CDCE62002

I am planning on using the CDCE62002. Table 18 from the datasheet lists various supported loop filter configurations. What I would like to know is how I can determine the effective loop bandwidth, phase margin, phase noise, etc for each of these Table 18 settings. For example, I am doing schematics now and I need to specify the values of R3 and C3 but how do I know what R-C values to put down if I don’t know the resulting loop bandwidth or phase margin for my configuration?

Here are some of my configuration

PFD frequency = 31.25MHz

VCO frequency = 2000MHz

Pre-scaler Divide ratio = 2

over 13 years ago

0 Julian Hagedorn over 13 years ago

TI__Mastermind 20900 points

Hello Chris,

you can use the software http://www.ti.com/litv/zip/scac112b to setup the device configuration and then click on "Loop filter" to calculate the Loop filter settings for the internal settings.

note: in a few days we will release an updated version of this software.

Best regards,

Julian

0 Chris Cotton1 over 13 years ago in reply to Julian Hagedorn

Prodigy 80 points

Hi Julian,

Thanks for your response but I had tried using that tool. When I click on the Loop Filter Tool button, I get a pop-up message that says "Please wait, the Loop Filter Tool is running" but nothing else happens even if I let it sit in that state indefinitely. Eventually, after nothing happening for a long time, I click on the X to remove the window. So I really need a verison of this tool that works for me.

By the way, I am running on Windows 7 64-bit OS is that makes any difference.

Thanks,

Chris

0 Julian Hagedorn over 13 years ago in reply to Chris Cotton1

TI__Mastermind 20900 points

Hello Chris,

please try to use the latest GUI from the Web, that should fix this problem.

http://www.ti.com/litv/zip/scac112c

best regards,

Julian

0 Chris Cotton1 over 13 years ago in reply to Julian Hagedorn

Prodigy 80 points

The updated version seems to be working. Thank you for your help.

Best regards,

Chris

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How to Predict CDCE62002 Loop banwidth