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ADS131M08: Simultaneous sampling ADC selection for strain measurements

Venkatesh indla
Prodigy 50 points
Part Number: ADS131M08
Other Parts Discussed in Thread: INA350, ADS131E08

We are looking for an simultaneous sampling ADC which can be used to measure strain in quarter bridge configuration. It has to be used in conditions where very slow/static as well as impact stress is applied. Hence simultaneous sampling is preferred.

For better accuracy, data averaging would be done.and hence a higher sampling is required.

The number of channels required are 16. Supply voltage for the bridge would be 5 V and strain gauges of 350 Ohms with a gauge factor of 2 will be used.

We are looking for a strain resolution of 2 microstrains.

Have been exploring ADS131M08 for the said purpose.

Kindly confirm if this ADC can be used for this application and if there are any specific points that have to be taken care of while using this ADC for such precision application.

Also please suggest if any economical difference amplifier is suitable for buffering the input, we may not need any gain at the buffer stage. (ina350 is in consideration)

Thankyou

ivr

  • 0
    TI__Mastermind 45785 points

    Hello ivr,

    Thank you for your query on E2E forum. Please see key difference between ADS131M08 and ADS131E08 solution for the bridge application as below, also two block diagrams which were created by my colleague (Bryan) are shown below, please let me know if you have any questions.

    • ADS131M08 only supports 3.3V operation and the external reference voltage is limited to 1.25V (1.3V max). A precision resistor divider as shown in the following block diagram is required to divide the bridge excitation voltage down to feed it to the ADC for a ratiometric measurement. A buffer can also be required as the ADS131M08 does not have an integrated VREF buffer.
    • ADS131E08 can support +5V excitation voltage directly and no divider or buffer is required, also it can support an external VREF up to +5V for a true ratiometric measurement. ADS131E08 offers low gain settings (up to 12). In many cases the noise performance at those low gains is sufficient.

        

    Best regards,

    Dale