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How to reset vco sub system in HMC1034?

Question asked by IHPGY on Jan 30, 2018
Latest reply on Feb 2, 2018 by IHPGY

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)

 

02 000019

06 2003CA

07 00004D

09 003FFF

0A 002044

0B 07C061

0F 000081

10 0000B2

11 080002

13 001259

05 001628

05 0060A0

05 006110

05 000000

03 0001F2

 

where the input reference frequency is 100MHz. The PFD compared freqency is 4 MHz.

Could you give me some advices? Thank you very much.

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