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trf372017 phase noise

I am using the TRF372017 Evaluation board.I had some concerns about the phase-noise performance i am observing. I provide a regulated 5V DC power input. I have tried  the on-board regulator for 3.3V and also tried out an external 3.3V regulator. The closed loop phase noise performance (1GHz carrier for my application) is much worse in comparison to datasheet plots. The EVM document also mentions that on-board regulator (for 3.3V) should not be used for high performance applications. The TRF372017 noise analysis document shows measurements done with lab power supplies which are much cleaner. But this will not be possible in battery operated systems on the field.

I am trying to figure out if the phase noise performance is just related to power supply issues? The EVM loop filter is optimal for 1.6MHz fpfd. Can we use the same loop filter for higher PFD frequency and achieve better phase-noise ? Any recommendations for power supply design using linear regulators for this device ?

 

Thanks! AB

  • Using the wrong regulator or power supply has been shown to have a nearly 20dB impact on in-band phase noise with the TRF3720 PLL / VCO.

    The best available regulator family for phase noise performance is the TPS74401 / TPS74201. These regulators lead to performance that is very close to that of the best known linear power supply.