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ADF4156 Design Issue at 1911.642 MHz

Question asked by humayunzahid on May 1, 2014
Latest reply on May 19, 2014 by Brigid.Duggan

Hello!

 

I've been using ADF4156 to design Local Oscillators at frequencies in the range of 5 to 6 GHz.

 

I use ADISimPLL and Fraction N software for the design.

 

I haven't faced any difficulties in the LO design at the above mentioned frequencies; but, i am facing difficulties in designing a LO at 1911.642 MHz.

 

The LO worked fine initially, but, strangely enough, it stopped working afterwards.

 

The charge pump output voltage is at 0.4V to 0.5V no matter what register configuration i use.

 

Further, the PLL chip gives out 5V at the charge pump out if i only enable the charge pump supply.

 

I've also designed a test PCB of ADF4156, but the PLL chip responds the same way.

 

Kindly help me in resolving this issue.

 

Am i programming the chip wrong?

 

It should not be the case as the LO was working initially.

 

An example for designing the LO at 1911.642MHz using Fraction N software and ADISimPLL would be highly helpful.

 

Thanking you in anticipation.

 

With best regards,

Humayun Zahid

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