LMX2492: Looking for PLL chip featuring no internal VCO and minimun N divider value down to 1

long yong

Part Number: LMX2492

Hi TI experts,

I'm looking for PLL chip featuring no internal VCO and minimun N divider value down to 1, and frequency range covers 2700MHz，do you have any suggestions?

thx!!

1 month ago

0 Noel Fung 1 month ago

TI__Guru* 84720 points

Hi Long,

We don't have such device.

What kind of performance specification that you are targeting for that drive the requirement of minimum N = 1?

0 long yong 1 month ago in reply to Noel Fung

Prodigy 20 points

Hi Noel, we want to improve in-band phase noise by using an offset LO reducing N to 1, since PLL_flat_noise=PLL_FOM+10log(Fpd)+20log(N), that should work, right?

0 Noel Fung 1 month ago in reply to long yong

TI__Guru* 84720 points

Hi Long,

I see. What is your target close-loop in-band phase noise at 2.7GHz carrier? I can check to see which synthesizer can meet your requirement.

0 long yong 1 month ago in reply to Noel Fung

Prodigy 20 points

Hi Noel,

The target is -124@1k，-135@10k，-142@100k.

0 Noel Fung 1 month ago in reply to long yong

TI__Guru* 84720 points

Hi Long,

1k and 10k phase noise is dominated by the 1/f noise of the PLL, as long as you can find a PLL with this 1/f specification, you may not need N=1.

Currently, we don't have product meets this 1/f requirement.

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LMX2492: Looking for PLL chip featuring no internal VCO and minimun N divider value down to 1