HMC835 Manual calibration

I have an HMC835 working quite well in my system.  I want to speed up the tuning by using manual calibration.  I am able to successfully read back any/all registers but after tuning to a new frequency (integer mode) when I read back register 0x15 I always get the factory default instead of the currently tuned frequency data.

Is there some other register setting that causes the auto-calibrated data to appear in register 0x15, or is there some special sequence that causes this



  • +1
    •  Analog Employees 
    on Jan 19, 2021 10:31 AM 1 month ago

    Hi Fred,

    The readback and write registers are different for manual calibration. Register 0x15 is used only to write the VCO parameters. The auto-calibrated data can be read from register 0x10. The VCO core and capacitor is not separated in register 0x10. You can consider as 0x10[4:0] as VCO capacitor and 0x10[7:5] as VCO core selection. In other words write the readback value 0x10[7:0] directly to register 0x15[8:1].