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ADAU1452 clock generators - How to choose N and M

Question asked by eingber on Apr 12, 2016
Latest reply on Apr 22, 2016 by DaveThib

I'm using a 12.000 MHz oscillator input to ADAU1452 XTALIN/MCLK, and need to operate at 32.000 kSamples/second. With Divider at 4 so Input to PLL is 3.000 MHz, and Feedback Divider at 96, so System Clock is 288.000 MHz, I can use the combinations of N and M shown below to get exactly 32.000 kHz Base Output Frequency (using Clock Generator 3 which has 16-bit registers for N and M).

 

My question is, does it matter which N-M pair I actually use? For example, is the PLL more stable with some combinations rather than others? Any other considerations?

 

Thanks!

Ed

 

For MCLK = 12.000 MHz, Divider = 4, Feedback Divider = 96 for Base Output Frequency of 32.000 kHz from Clock Generator 3…

   

NM
1281125
2562250
3843375
5124500
6405625
7686750
8967875
10249000
115210125
128011250
140812375
153613500
166414625
179215750
192016875
204818000
217619125
230420250
243221375
256022500
268823625
281624750
294425875
307227000
320028125
332829250
345630375
358431500
371232625

 

Does it matter which N-M pair I use?

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