I need a ~70MHz oscillator with low frequency drift (less than 1%) over a wide temperature range (10°C to 50°C).

I dont have any experience with oscillators, so I have no idea which type of oscillator I should use:

  • Colpitts Oscillator
  • PLL Clock multiplier (e.g. ICS501)
  • Crystal oscillator (e.g. this one here)
  • Silicon oscillator (e.g. LTC6903)

I have access to a microcontroller, so I think the simplest solution will be just generating a clock signal and then multiplying it by using a PLL?

I dont care about the wave form, and I dont need to adjust the frequency -- fixed frequency is fine.

  • 3
    \$\begingroup\$ Just off the cuff I'd say you want a crystal oscillator. Even relatively pedestrian crystal oscillators have a spec of about 100 ppm / K. You've got a 40 K range so this (back of envelope) estimate says to expect 0.4% over that range. There's another issue perhaps. That's initial accuracy and how stable that is over accumulation of time and temperature changes and/or changes due to varying atmospheric pressure and/or humidity. I generally trust manufacturer specs related to precision far more than I trust a manufacturer's spec for accuracy. I rarely take an accuracy spec for granted. \$\endgroup\$
    – jonk
    Nov 12, 2022 at 20:04
  • 2
    \$\begingroup\$ @jonk crystals are much better than 100 ppm/K. They are usually +/-100 ppm across a full range of temperatures. \$\endgroup\$
    – Andy aka
    Nov 12, 2022 at 20:52
  • 2
    \$\begingroup\$ @Andyaka Yup. My brain was on vacation! Thanks for the correction!! I was just thinking of the 100 ppm spec and I made up the "per K" out of whole cloth. My apologies for my confusion. BenK, crystals will be a lot better over temperature variation than I mentioned. Andy is right! \$\endgroup\$
    – jonk
    Nov 12, 2022 at 20:57
  • 2
    \$\begingroup\$ It happens to the best of us. Made the same identical mistake as you (also on SE) do'h \$\endgroup\$
    – Andy aka
    Nov 12, 2022 at 21:01
  • 1
    \$\begingroup\$ For even better temperature stability use a oven-controlled crystal oscillator. \$\endgroup\$ Nov 14, 2022 at 7:20


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