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Transient simulation of a crystal oscillator

PeppeW90

Hi,

I'm simulating a 80MHz crystal oscillator, so it is a circuit with an high Q (around 80k).

I want to run a transient simulation of this circuit, and I'm experiencing that the results are a lot dependent of the step and maxstep of the transient simulation. As regards the accuracy, I set it to "moderate".

I want to simulate the start-up time of the XO: if I set the step to 1n and maxstep to 2n, I simulate a start-up time of around 400us, if I use 10ns of step, I find around 1ms of start-up.

So I'm wondering what is the best setup in this case, what values to chose for step and maxstep and if moderate as accuracy is ok

Thanks

  • Tawna
    I recommend using Spectre RF, harmonic balance (hb) for simulating crystal oscillators. It is more accurate and likely faster as well.
    I also recommend using errpreset=conservative for crystal oscillators, whether you are using Spectre Transient (tran) or RF Harmonic balance (hb). I do *not* recommend tweaking options. On Cadence Online Support https://support.cadence.com there are good articles on simulating crystal oscillators.
    11534912 Recommended setup for running PSS/HB on Voltage Controlled Crystal Oscillators (VCXO)
    11851364 to Speed Up Transient Simulation of Crystal Oscillators
    20451308 Crystal Oscillator Simulation using SpectreRF (Rapid Adoption Kit)
    and many others...

    best regards,
    Tawna

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