There is a problem in my project when using HMC1034 as a ADC Clock to generate 996MHz and 640MHz. When the temperature raised high to +80℃, Power up HMC1034, the PLL fail to lock and the vco subsystem do not react when control through Reg 05H.
Read the register of Reg 00~0F, the readback values are right and the PFD is working as registers control. But the vco subsystem do not react when write the vco registers through Reg 05H. After power up and normal registers set, the VCO autocal system seam to unwork. Reg 10H readback values are 00H, but the free running vco frequency is around 1440MHz.
When we set the Reg 0AH 2844H to disable autocal mode and use manual vco calibration, set Reg 05H AD00H to program the vco switch settings directly. The vco seam to be dead and do not respond, the free running vco frequency is still around 1440MHz.
The registers settings are as followes(Autocal mode)
where the input reference frequency is 100MHz. The PFD compared freqency is 4 MHz.
Could you give me some advices? Thank you very much.