some questions about ADF5901 and ADF4159

Hi,

i use ADF5901 with ADF4159. But i have two questions about ADF5901. 

1. Does the output power of TX out of ADF5901 can be changed from -20dBm to +8dBm  by change the Tx AMP CAL REF CODE? i connect a amplifier after ADF5901. So I should check this.

2. I think the VCO-CAL  in ADF5901 is useless  when  i use ADF4159 to control the Vtune of VCO in ADF5901. So i want to know how do i set the N-Divider and R-Divider in ADF5901?  

 Because in a PLL,the  N-divider and R-divider i really use is  in PLL just the ADF4159 but not in VCO just the ADF5901.

look forward for your reply.

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  • 1. Yes output power is adjustable by using TX_AMP_CAL_REF_CODE

    Power should be check at the output of any additional amplifier after the ADF5901.

    2. VCO-CAL  in ADF5901 is not useless and VCO calibration is needed on the ADF5901 to ensure the VCO is centered in the band of operation.

    The N-Divider and R-Divider on the ADF5901 should be setup for the center frequency of operation. 

    Example from initialization sequence in data sheet.

    REFin = 100MHz, R-Divider = 2 => RCLK = 50MHz

    Center Frequency = 24.125GHz, divide-by-2 version feedback to N-Divider (12.0625GHz) = > N = 241.25

    => INT = 241, FRAC_MSB = 1024 (i.e. 1/4) 

Reply
  • 1. Yes output power is adjustable by using TX_AMP_CAL_REF_CODE

    Power should be check at the output of any additional amplifier after the ADF5901.

    2. VCO-CAL  in ADF5901 is not useless and VCO calibration is needed on the ADF5901 to ensure the VCO is centered in the band of operation.

    The N-Divider and R-Divider on the ADF5901 should be setup for the center frequency of operation. 

    Example from initialization sequence in data sheet.

    REFin = 100MHz, R-Divider = 2 => RCLK = 50MHz

    Center Frequency = 24.125GHz, divide-by-2 version feedback to N-Divider (12.0625GHz) = > N = 241.25

    => INT = 241, FRAC_MSB = 1024 (i.e. 1/4) 

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