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AD5791 max SCLK frequency?

Question asked by PwrElec on Sep 14, 2011
Latest reply on Sep 14, 2011 by PwrElec

Hello all


I am very happy to be here.


I am a student doing a small DAC project, and am looking at AD5791. I am a bit confused about what the max SCLK frequency.


I have attached the data sheet.


On the first page under 'Features' I read:

35 MHz Schmitt triggered digital interface


On page 5 under the timing characteristics table I read:

Maximum SCLK frequency is 35 MHz for write mode and 16 MHz for readback and daisy-chain modes.


So far so good. Here is my problem:

On page 20 in the description of the 'input Shift Register' I read:

Data is loaded into the device MSB first as a 24-bit word under the control of a serial clock input, SCLK, which can operate at up to 50 MHz.


Now, I understand that it only can operate @ 16 MHz in readback and daisychain mode. But what I dont understand, when/where does the 50 MHz come in the picture?


Thank you very much