We found the problem for HMC764 on frequency locking under integrated mode & bad phase noise once locked.Below is our inquiry, pls help to clarify. Thanks.
1. How is the register setting sequence due to can't find it on datasheet ? Below is our register setting & writing sequence.
1) 00h 1 RST
2) 02h 3 R=3
3) 03h 174 N=372
4) 0Bh 878 negative slope
Fref: 30MHz (external SG) Fout: 7.44GHz
2.How to turn on frac-N mode ? As datasheet description as below, it doesn't work while setting reg 9 [9:7] to "100" (for 220uA charge pump offset) & 011 for reg 6[12:10].
Note: To Enable Frac Mode: Set Reg 6 [12:10]= 011
Also, Reg 9[9:7] or Reg 9[4:2] must be adjusted to mitigate spurs in frac mode (Dn or Up Leakage)
3.For N value described as below, it shouldn't need to divide by 2. In reality, the value of N needs to divide by 2 as above "N=372" for 7.44GHz frequency out. If I misunderstand for it ?
4.For phase noise and loop filter is as below once lock ,it really bad on SSB. Do you have some recommend for it ?