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Oscillator for LTC6948 Ultralow Noise 0.37GHz to 6.39GHz

MM
Mike Monett
Tue, Mar 14, 2023 6:01 PM

Looking for info on the oscillator for the LTC6948 Ultralow Noise 0.37GHz
to 6.39GHz

https://www.analog.com/en/products/ltc6948.html?ADICID=SYND_WW_P682800_PF-octopart#product-overview

  1. Is it considered "low noise"

  2. How does it achieve low noise

Thanks

Mike

Looking for info on the oscillator for the LTC6948 Ultralow Noise 0.37GHz to 6.39GHz https://www.analog.com/en/products/ltc6948.html?ADICID=SYND_WW_P682800_PF-octopart#product-overview 1. Is it considered "low noise" 2. How does it achieve low noise Thanks Mike
JM
John Miles
Thu, Mar 16, 2023 3:44 AM

-----Original Message-----

  1. Is it considered "low noise"

  2. How does it achieve low noise

It's an OK part, but there are better ones out there.  Notice that you don't
get the whole 0.37 GHz-6.39 GHz tuning range from one part number.  You have
to buy the right suffix for the frequency range you're interested in.
That's not true for virtually any of its competitors.

Some of the key performance numbers are the normalized figures of merit for
PN and flicker noise.  A couple of generations ago, -226 and -274 were
great, but they are nothing special now.  ADF4377 is the best currently
(un)available, at -239 and -287.  In addition to the usual improvements in
circuits and processes, the big wins come from raising the phase detector
frequency (hence lower N factor) and adding more switchable tank circuits to
the VCO, which lowers the tuning sensitivity in any one band segment.

-- john

> -----Original Message----- > 1. Is it considered "low noise" > > 2. How does it achieve low noise > It's an OK part, but there are better ones out there. Notice that you don't get the whole 0.37 GHz-6.39 GHz tuning range from one part number. You have to buy the right suffix for the frequency range you're interested in. That's not true for virtually any of its competitors. Some of the key performance numbers are the normalized figures of merit for PN and flicker noise. A couple of generations ago, -226 and -274 were great, but they are nothing special now. ADF4377 is the best currently (un)available, at -239 and -287. In addition to the usual improvements in circuits and processes, the big wins come from raising the phase detector frequency (hence lower N factor) and adding more switchable tank circuits to the VCO, which lowers the tuning sensitivity in any one band segment. -- john