Please help on how to design PLL loop filter for specific loop band width? ( what is loop bandwidth anyway?). I have charge pump current and VCO sensitivity as input.

Thanks &Regards,
V.Veerasamy

 

Try this pdf application note http://www.national.com/an/AN/AN-46.pdffor some background reading ...

 

Please help on how to design PLL loop filter for specific loop band width? ( what is loop bandwidth anyway?). I have charge pump current and VCO sensitivity as input.

Thanks &Regards,
V.Veerasamy

What is the part number of the PLL device have you chosen to use? And how are you planning to use the PLL?

hgmjr

 

Thanks t_n_k. To hgmjr: I am using PLL with integrated VCO (AD4350).

 

Thanks t_n_k. To hgmjr: I am using PLL with integrated VCO (AD4350).

Use ADIsimPLL: http://www.analog.com/adisimpll

 

Thanks t_n_k. To hgmjr: I am using PLL with integrated VCO (AD4350).

Are you refering to the ADF4350 made by Analog Devices? I could not locate any information on the AD4350.

hgmjr

 

to hgmjr: Yes i am using ADF4350.
to Tesla23: I am using AdsimPLL. but in AdsimPLL it assumes phase detector frequency and channel spacing are same. For me they are different

 

to hgmjr: Yes i am using ADF4350.
to Tesla23: I am using AdsimPLL. but in AdsimPLL it assumes phase detector frequency and channel spacing are same. For me they are different

If you are doing a Fractional-N design then make sure that you select this on ADIsimPLL, then you can select the modulus on the Chip page, and you will see the channel spacing is different to the PD frequency.

As an example, if you choose the ADF4350 on the first page of the wizard and accept all the default parameter values you will get a Fractional-N design where the channel spacing is different to the PD frequency.