AnsweredAssumed Answered

CLKModeSelect voltage in AD9954 Eval Board

Question asked by Rice on Sep 2, 2011
Latest reply on Sep 14, 2011 by JLKeip



i see that, in order to make the DDS consider the XTAL input signal I have to show a '1' to the CLKModeSelect input. But, I see that when I select that option in the debugging software, it gets 2.71 V, instead of the spectable 3.3V. In my custom board, I put 3.3V in that pin... but then I got a problem that the DVDD and AVDD pins got around 2.2 V instead of the 1.8V... so I guess it is 2.7 the right value.


Can anybody tell me why is that?


Would a good solution to use a resistive voltage divider from the 3.3 V regulator in order to generate the 2.71V?


Thank you in advance