AD9218, what will the negative values be in binary mode?

When my DAC output is from 0-1V, and is fed into 10-bit AD9218 which is set to binary mode, what binary value will I get when the input is -10mV?

Reply to
Frank
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I assume you mean -10mV AC coupled into the AD9218 (it is internally biased at 1/3Vdd)

You would have 1/200 of the negative dynamic range, or 1/100 of the span range which gives -10/1024.

As the output is set for 2s complement, the output will run from +511 to -512 (Hex = 0x1FF at +511 to 0x200 at -512) for an input of 1Vp-p, so in this case, you should get 3F6, rounded to the nearest integer. (-10 decimal)

Cheers

PeteS

Reply to
PeteS

further to my other reply, if you are using offset binary, then you will get N[off] - 10 (decimal). The output of the DAC at Vin(centre) should be 0x200, so you would get 1F6.

Cheers

PeteS

Reply to
PeteS

On 28 Nov 2005, Frank put down his happy meal and blurted:

I'm lovin' it.

Reply to
Von Heler

Thank you Peter.

My digital output is from 0-1024 (1MHz sine wave 0 -> -1, 1024 -> +1) and fed into the

10 MSBs of DAC (TI DAC290x-EVM). Due to noise, the DAC has some below zero values on oscilloscope (-20mV ~ 0.8V). When I connected this signal to ADC, how do I ensure that the digital output is the same (or nearly the same) value of my original digital input? (The requirement is such that after I captured the ADC O/P with logic analyzer, plotted in graph of 0~1024, it shows a sine wave without bad codes).

Reply to
Frank

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