This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

ADS1258: ADS1258 - 5V Ref

Part Number: ADS1258
Other Parts Discussed in Thread: OPA228, OPA320, REF6250,

For a prototype project i need to Measure the environmental data like Temperature, Humidity, IR Radiation, etc. I am planning to use OPA388 and INA326 stages as signal conditioning pre-amplifiers with Low pass filter.

1) In my design the MUX out put will be directly connected to the ADC IN. Planning to use OPA320 / OPA228 as input buffers to the MUX. Which would be the best option Please suggest.

2) I am planning to use ADS1258 with 5Volt Reference. In the Datasheet it is mentioned typical Ref as 4.096V. and ADC reads full scale at 1.06*Vref. In that case i will read fullscale at 4.34V.
My input Swing 0 to 5V, Can i give 5V reference? planning to use REF6050 / REF6150 / REF6250. Which would be the best option Please suggest.

Thanks in Advance.

  • Hi Shyamsudar,

    I think I can help answer those questions...

    1. Both opamps are good options, but there are some differences in characteristics that you'll have to decide for your application which is better suited...
      1. OPA228 is higher power, but has a lower offset, lower offset drift, and lower noise.
      2. OPA320 has a lower input bias current and is slightly lower in cost. If your input signal to this opamp stage is coming from one of your signal conditioning pre-amps, then input bias current is likely not a concern.
      3. Both opamps have a dual package option.

    2. Correct, full-scale occurs at 1.0666...* Vref, or 4.369V. You can also use a 5V reference with the ADS1258. All the REF6x50 devices are very similar. The main difference is the voltage coefficient of temperature, with the REF6250 having the lowest temp coefficient (3 ppm/degC).

    I hope that helps!

    Best regards,
    Chris