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a dummy question about pll in 1701

Question asked by Skfir on Jul 31, 2013
Latest reply on Aug 1, 2013 by BrettG

Hello people, I am going to build my own board with the adau1701 so I have been violently reading through the datasheet. The thing is I am a bit confused with PLL settings. In the paragraph "setting maste clock/pll mode" it is written: "If the ADAU1701 is set to receive quad-rate signals (by reducing the number of program steps per sample by a factor of 4 using the core control register), the master clock frequency must be 16 × fS, 64 × fS, 96 × fS, or 128 × fS"  But the thing is I use AD adau1701-miniz board for maketing and run a 192khz project, it works fine and yet when I checked the schematic of the board, I found out that the PLL pins on the board were configured to have 256xfS! So I am confused... Does all that mean that if I want to run a 192khz project, I must use a 24mhz resonator and set the PLL pins to 128xfS?? But if so, why the adau1701-miniz board still runs my 192khz project being set up to yield 256xfS?

Guyz, I understand that perhaps this question has been asked with some variations for many times most probably, but I read several topics and still cannot understand. Please help!!


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