We are encountering a lock problem with ADF5355 when we bypass the AUTOCAL to generate look up table for faster lock times.

We found AN-1353 application note that include bypass VCO Calibration for ADF 5355. This note is explained VCO Readback procedure in detailed. We follow this procedure to obtain VCO core band bias, but we don’t achieve lock signal output of ADF 5355.

My Registers:

  • R10 DB[28:26]=1       (001)    
  • R7 DB[14:12]=6       (110)    
  • R4 DB[29:27]=7       (111)    
  • R2
  • R1
  • R0 (AUTOCAL=1)
  • Wait MUXOUT until it is logic high
  • R7 DB[14:12]=7       (111)                     set to vco readback
  • R10 DB[28:26]=3       (011)    
  • R10 DB[28:26]=0       (000)                     Normal Mode
  • R7 DB[14:12]=0       (000)                     Normal Mode
  • R4 DB[29:27]=6       (110)    

 This loop is repeated as required.