ADF4159 and HMC6380 VCO

 Hi, 

I intend to generate a sawtooth waveform (freq from 8GHz to 8.5GHz using the HMC6380LC4B VCO

Can this be achieved without the use of an op amp?

Rgds

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  • +1
    •  Analog Employees 
    on May 21, 2021 9:06 AM

    In general yes it can be possible to use a wide tuning range VCO without an active loop filter but only if the intended VCO frequencies to be used cause the voltage tuning range to be on the lower end and within the PLLs CP voltage range. 

    Looking at the HMC6380's datasheet it looks like it would tune 8GHz at ~2V vtune and 8.5GHz at around 3V vtune, which are within the ADF4159's CP spec when used with a passive loop filter. I would recommend testing a few different HMC6380 devices to verify you have enough margin with any part-part tuning sensitivity variations there may be

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  • +1
    •  Analog Employees 
    on May 21, 2021 9:06 AM

    In general yes it can be possible to use a wide tuning range VCO without an active loop filter but only if the intended VCO frequencies to be used cause the voltage tuning range to be on the lower end and within the PLLs CP voltage range. 

    Looking at the HMC6380's datasheet it looks like it would tune 8GHz at ~2V vtune and 8.5GHz at around 3V vtune, which are within the ADF4159's CP spec when used with a passive loop filter. I would recommend testing a few different HMC6380 devices to verify you have enough margin with any part-part tuning sensitivity variations there may be

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