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ADS1282 Voltage reference recommendations.

Other Parts Discussed in Thread: ADS1282, REF5050, TIPD114

Hi

I am currently designing a four channel data acquisition board using 4 ADS1282. Three of the channels are connected to low impedance geophones and the last channel is connected to a piezo based hydrophone (very high impedance). The bandwidth of interest is 3-170Hz.

All ADs share the same voltage reference which comprises of one REF5050. To lower the voltage reference noise, I have connected it through a low pass filter consisting of 1k resistor and a 100uF tantal on each AD. 

Is this a good Vref solution to get the best performance, lowest noise, out of the ADS1282 or could it be done better?

  • Hi Terje,

    Welcome to the TI E2E Forums!

    I looked at a similar question in the following E2E thread:

    The problem I found was that a single REF50xx had trouble driving multiple ADS128x reference inputs. I ran a simulation and found that the REF50xx was not re-charging the external reference capacitors fast enough. This could cause a higher than normal gain error. While some of this gain error could have been removed through calibration, it is difficult to say how this gain error might have changed over time and temperature. To be save, I would recommend buffering each reference input, if you can. I would recommend the reference driver shown in TIPD114:

    Otherwise, if buffering is not an option, try to use much smaller R and C values (<25 Ohms and < 1uF) to reduce the gain error (larger values take longer to recharge and will result in larger gain errors).


    Best Regards,
    Chris

  • Thanks for good answers. I will add buffers on each ADS1282 Vref input.

    Kind Regards
    Terje