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ADS1292 noise measurement

Ernesto Gonzales
Prodigy 225 points
Other Parts Discussed in Thread: ADS1292

I'm using the ADS1292 with a gain of 12, 125SPS and low-pass filtered input electrodes in all channels. It's a single-supply design.
The bias signal RLDREF is generated internally by setting RESP2 accordingly.

However, when I short the inputs with the appropiate registers, I thought I was going to see a noise signal whose DC level was about 1.5 V (my VDD is 3V). However, I only see values on the order of 10uV near at 0V. Why could this be?

  • 0
    TI__Mastermind 38745 points
    Hey Ernesto,

    This is the case because the ADS1292 measures voltages differentially. The output will be measured as (INxP - INxN)*PGA. In your case when the inputs are shorted, the measurement comes out to something in the neighborhood of (1.5 V - 1.5 V) = 0 V.

    Brian