Recently I have been comparing the phase noise of the HOlzworth HX4210 and the LTC7957-4. I have found that the performance of these devices is comparable with a 10MHz sinewave input with a PN noise floor below -160dBc/Hz. For offsets below 100Hz the LTC6957-4 is quieter and for offsets below 50Hz or so is lower than that of my measurement setup. I merely mounted the LTC evaluation board in a diecast metal box to reduce the effect of air currents on the LTC7957-4 and used an ultra low noise 3.3V power supply (Abracon) to minimise the power supply contribution to the measured phase noise. Achieving a phase noise performance equal to that on the datasheet was relatively easy. In fact for low offsets the phase noise is lower than that shown on the datasheet.
I've also measured the phase noise of a comparator based sine to CMOS converter and its PN floor is about 20dB higher than that of the LTC6957. On completion of measurements PN plots for the various sine to square conveters tested will be added to the web pages I maintain on Didiers site.. Bruce _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
