The Designer's Guide Community Forum https://designers-guide.org/forum/YaBB.pl Design >> Analog Design >> Defining PLL closed loop  bandwidth https://designers-guide.org/forum/YaBB.pl?num=1392165224 Message started by analog geek on Feb 11th, 2014, 4:33pm

Title: Defining PLL closed loop  bandwidth Post by analog geek on Feb 11th, 2014, 4:33pm Very basic question about PLL.. If it is written that PLL works at 2 GHz, how will you define PLL close-loop bandwidth?...Also whats the relation between VCO bandwidth in PLL and just PLL?..are they same?... :-[ If I am designing Linear Regulator for VCO 8-), which bandwidth should I worried about?.. Thanks :P

Title: Re: Defining PLL closed loop  bandwidth Post by carlgrace on Feb 11th, 2014, 9:07pm PLL bandwidth is defined as the 3 dB frequency of reference phase modulation at which the PLL will begin to lose lock.  Don't confuse it will the PLL frequency (VCO or natural frequency). The PLL bandwidth is set by your loop filter not your VCO.  Although it is related to the loop's natural frequency it is primarily set by your damping factor. The BW you should be worried about for the linear regulator is the closed-loop BW.  The PLL rejects VCO noise up the the closed-loop bandwidth (transfer function from VCO to output is high pass).

The Designer's Guide Community Forum » Powered by YaBB 2.2.2! YaBB © 2000-2008. All Rights Reserved.