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Design >> RF Design >> Choosing PLL: ADPLL or Fractional N or Integer N
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Message started by mixed_signal on Jun 11^th, 2014, 8:37pm

Title: Choosing PLL: ADPLL or Fractional N or Integer N
Post by mixed_signal on Jun 11^th, 2014, 8:37pm

Hi experts,

I have the following requirements for my frequency synthesizer PLL

center frequency= 700MHz, channel bandwidth=300KHz
channel switch time<=100us
Phase noise<= -100dBc/Hz@ 1MHz offset

I want to make the PLL as low power as possible (<700uW). Which is the most suitable architecture:
All digital PLL
Integer N PLL (Type 1 or Type2)
Fractional N PLL

With type2 integer N PLL: Loop BW=1/10th of channel BW=30KHz. This makes it difficult to achieve channel switch time of <100us

Title: Re: Choosing PLL: ADPLL or Fractional N or Integer N
Post by hwa_chan on Jun 20^th, 2014, 8:44am

digital pll

Title: Re: Choosing PLL: ADPLL or Fractional N or Integer N
Post by loose-electron on Jun 20^th, 2014, 7:42pm

Your phase noise is the big issue. All digital at that phase noise number? I doubt it.