LMX2594: What will IncludedDivide be if channel divider is 2?

shen jie

Part Number: LMX2594

Tool/software:

Hi,

I use the two LMX2495 in my board, and want to sync the output clock(3932.16MHz) between them. As below figure.1 shown, my configuration is that Fosc =122.88MHz and Fout = 3932.16MHz。

It conform to SYNC Category 1, so I set VCO_PHASE_SYNC=1. I find channel divider=2 but IncludedDivide=4 in the figure.3. My understanding is that IncludedDivide come from channel divider, so IncludedDivide must be less than channel divider. But now, IncludedDivide are bigger than channel divider. My questions are:

1. Whether will this configuration work normally?

2. N Divider(16) will turn red that the tip show that the minimum N divide for any modulator order is 28 , but I don't use MASH order function. Whether will this red warning impact my configuration?

Figure.1

Figure.2

Figure.3

Figure.4

Thanks in advance!

Best regards!

Jason

10 months ago

0 Noel Fung 10 months ago

TI__Guru** 108550 points

Hi Jason,

includeddivide comes from SEG1, so IncludeDivide is either 4 or 6.

Because IncludedDivide is 4, N-divider becomes 16 and therefore violating the min. N divider requirement,.

you have to use a smaller fpd to make N-divider bigger. Since it is an integer channel, you can set MASH_ORDER = 0.

0 shen jie 10 months ago in reply to Noel Fung

Intellectual 265 points

Hi，Neol:

So the correct understanding as below figures shown, right?

when VCO_PHASE_SYNC=0, feedback to PLL_N（=128） after VCO(Green line ) and output clock after 1/2(Blue line, also named SEG0).

When VCO_PHASE_SYNC=1, feedback to PLL_N（=128） after Divider by 2 or 3 (Green line, also named SEG1 ) and output clock after 1/2(Blue line, also named SEG0).

Thanks in advance!

Best regards!

Jason

0 Noel Fung 10 months ago in reply to shen jie

TI__Guru** 108550 points

Hi Jason,

That is correct.

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LMX2594: What will IncludedDivide be if channel divider is 2?