DSB

Re: power supply of dds

Discussion created by DSB Employee on Aug 22, 2012
Latest reply on Aug 27, 2012 by DSB
Branched from an earlier discussion

We didn't use ferrite beads for the power supply pins on the AD9912 evaluation board. So, I don't have a specifc ferite bead recommendation. However, some of our high performance clocking parts do find ferrites beads are helpijng to reduce coupling between channels and supplies. The ferrite part number used there was BLM15X601SN1D (600 ohms) from Murata. So, I would start with that one first, if it were me.

 

In general, the PLL  phase noise performance is improved by running the PFD faster verses slower. Running faster uses less multiiplication to reach the final system clock frequency. So, picking the faster 100MHz TCXO could improve phase noise performance. Also, increasing the slew rate is typically a good thing too. So clippled sine wave sounds like a positive for slew rate.

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