AD9106 Questions

Question

Hi, I'm working on getting the AD9106 up and running and have a couple questions: 
 1) What is "xDAC INPUT CODE"? Is it a register value or something internal to the chip? It appears on pg. 22 of Rev. A of the datasheet in the section "DAC TRANSFER FUNCTION". I couldn't find it explained on the datasheet, but maybe I missed it. 
 2) Right now I'm using a single-ended 10.5 MHz clock from a microcontroller (Arduino Due). I am taking CLKN to ground via a 0.1uF cap and 39K resistor. How bad of a setup is this? I'm seeing a lot of jitter in my analog outputs (sine waves at 1 kHz). Are there other places the jitter could come from besides a jittery clock, or is the clock the likely culprit? 
 Thanks, 
 Pete

ADIApproved · Accepted Answer

xDAC INPUT CODE is the instantaneous 12b value delivered to DACx (x=1,2,3 or 4) by the internal waveform generator logic. The formula on page 22 shows how a 12b data value converts to an output current. 
 Generally, uP clocks are rather noisy and usually not very suitable for signal generation. Although you may get an output signal, it may not be as "clean" as you might like.

ADIApproved · Answer

HI - 
 I recommend that you not bother doing calibration. It doesn't change the gain accuracy very much. If do use calibration just leave the register values in their default state. 
 Thanks

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AD9106 Questions