Hi,
I am Mahesh, We are using HMC900 IC for our board.
We are trying to do RC Calibration sequence.
Externally 40MHz clock with 3.3Vpp square wave is given to filter.
As per datasheet HMC900LP5E, we are trying to do RC calibration.
For RC calibration following sequence we are followed.
1. In Reg 05h write value 25000 in decimal. (i.e. 1/40 MHz clock =25000ps).
2. In Reg 01h write value 46 in decimal.(RC Calibration enabled).
3. In Reg 04h write value 1 in decimal.
4. Reading the Reg 08h read value is 0x0b in Hex.
5. Reading the Reg 09h read value is 0xffc684 in Hex.
Using the Reg 09 value we are calculating the ctune, fBW_norm_coarse, fFine_Tune_ratio
ctune = 16762500 / 10370000.
ctune = 1.6164
fwanted = 11000000
fBW_norm_coarse = fwanted * ctune.
fBW_norm_coarse = 11000000 * 1.6164
fBW_norm_coarse = 17780858.24493
fFine_tune_ratio = fBW_norm_coarse / fBW_norm_coarse_typ
fFine_tune_ratio = 17780858.24493 / 11000000
fFine_tune_ratio = 1.6164
After calculating fFine_tune_ratio is exceeding the Calibration Code Look up Table.
Kindly provide your feedback.
With Regards,
Mahesh.
