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ADF4355-2 problem with registers

Question asked by Pingky on May 23, 2016
Latest reply on May 24, 2016 by Pingky

Hello. Our customer try ADF4355-2 and have some problems.

They try to archive 115 Mhz with 10Mhz Rfin, but have approximately 227 Mhz.

Wrong Rfout changes correctly with change  of output devider.

They try to disable negative bleed  and change MOD2 to gteater values  «MOD2 is the programmable, 14-bit auxiliary fractional modulus (2 to 16,383).» 

And try other manipulations with registeres.

MUXOUT  to R devider output gives 1 Mhz square as exprcted, but  when choose N devider there is no signal.

And customer got question about power supply pins 5,16. On figure 45 pin 5 AVDD not connected and customer made same layout. When they try to connect pin 5 to pin 16  (AVDD)  chip not starts. Question is what circuits powered by pin 5?

It seems that int +frac components and/or VCO works not correctly or problem with Registers.

 

 

 

4355-2.jpg

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