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How to set the register of HMC1032 to use it in integer mode?

Hi, 

I set the registers to get 250 MHz output for integer mode, shown below. My reference is 10MHz.  However, I could not get the integer phase noise graph same as that in the datasheet of HMC1032. The phase noise I measured is more looks like fractional mode one. Which registers should I write to set it as an integer mode? Except Reg 06h[11] = 0. Reg 06h[7] = 1. 

Here is my INIT:

hwr 0x0A 0x2045
hwr 0x0B 0xFC061
hwr 0x02 0x1
hwr 0x06 0x307CE
hwr 0x09 0x3264

hwr 0x05 0xF88
hwr 0x05 0x6310
hwr 0x05 0x2898
hwr 0x05 0x60A0
hwr 0x05 0x1628
hwr 0x05 0x7FB0
hwr 0x05 0x0

hwr 0x03 0x96

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  • Hi,

    Your register settings look correct.

    The datasheet plots are measured with 50MHz reference vs you have 10MHz. This change both increases the PFD noise and also modifies the loop filter response if you are using the same filter. You can simulate your configuration in ADIsimPLL and compare your results with measurements.

    A new loop filter design can be used to optimize the performance. However high reference reference (PFD frequency indeed) should be used for best performance. This can be also simulated in ADIsimPLL.  

    Regards, Kazim 

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  • Hi,

    Your register settings look correct.

    The datasheet plots are measured with 50MHz reference vs you have 10MHz. This change both increases the PFD noise and also modifies the loop filter response if you are using the same filter. You can simulate your configuration in ADIsimPLL and compare your results with measurements.

    A new loop filter design can be used to optimize the performance. However high reference reference (PFD frequency indeed) should be used for best performance. This can be also simulated in ADIsimPLL.  

    Regards, Kazim 

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