Hello,
I have an issue with verifying the input referred noise levels according to table 4 on the data sheet for my ADS1298R mmb0 evaluation board, my ADC register settings are the following:
I'm trying to read the input refered noise in Low power mode 5V analog supply and 4V reference, what I can verify is the noise for a PGA Gain = 1 this reads values close to 11.9uVpp like the spec sheet states:
however when I start increasing the PGA gain these numbers are not decreasing, for example for a gain of 12, I'm not reading anything close to 2.2uVpp and 0.4uVrms
using the scope analysis this is what I see:
I know the scope could be a little off but a quick visual inspection doesn't show the peak to peak voltage being close to 2.2uV
I feel like I'm missing something, any help will be appreciate it (I read the noise measurements notes on page 9 of the data sheet, it mentioned shorting the inputs, I also did this and no change).
Thanks in advanced
Rafael