AnsweredAssumed Answered

ADF4159 cannot lock

Question asked by jadanz on Jun 6, 2016
Latest reply on Jul 7, 2016 by rbrennan

First, We assembled our prototype with ADF4159 EV-kit and other ev-kits to generate FMCW. It works.

Then we went SMT for our prototype. The frequency can’t be locked, while all the parts we used on our prototype are the same as the one we assembled with EV-KITs.   

Therefore, we have checked both hardware and software as shown in below.

 

Hardware wise:

We found there is no charge pump current from cp pin.

We have checked:

  1. 1. We connected EVB-ADF4159 cpout to our loop filter & VCO freq, the freq. can be locked. Therefore, loop filter & VCO on our prototype board should be okay.
  2. 2. CLK: We used the crystal oscillator on our prototype board to drive EVB-ADF4159, the freq. can be locked.
  3. 3. RFin: The power level measured at RFin pin is big enough. ( at least 10dB higher than the power level we measured on the EVB-ADF4159)
  4. 4. The voltage level is correct on ADF4159 in our prototype board.

 

Based on the experiment we did, we think the hardware should be okay.

 

Software wise:

We have checked:

  1. 1. We bond wire the spi input signal (clk,LE,DATA) from EVB-ADF4159 to our prototype board and tried to read the MUXOUT. We were able to read the correct DVdd & DGND,

but for the rest, Rdiv, Ndiv and lock detect, we were unable to read the pattern and we couldn’t find related information on ADF4159 date sheet.

 

 

Is there any suggestion or experiment we can try? Many thanks!

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