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ADS131E08: ADS131E08 vref options

Jithesh Balan
Intellectual 440 points

Part Number: ADS131E08

Tool/software:

Hi Team, 

we are planning to use ADS131E08 in our design. we are planning to feed a vibration signal of 4KHz +/- 3.3V to ADS131E08 input. Is it possible? and what all the voltages we have to connect to DVDD, AVDD, VREFP and VREFN?. Please suggest another ADC part numbers also, if this requirement not meets with ADS131E08.

ADC should be sigma delta, and sampling rate should be more than 16ksps.

  • 0
    TI__Mastermind 49425 points

    Hi Jithesh Balan,

    I guess your input signal is a single-ended signal, so there are two solutions for you:

    • Bipolar power supply: ADS131E08 supports +/-2.5V power supply as shown in figure 67 in the ADS131E08 datasheet, however your bipolar input signal is higher than +/-2.5V power supply, so you will have to scale the bipolar input signal down to meet the ADC input requirement which is shown in the table 7.1 and 7.3 of the datasheet.
    • Unipolar power supply: ADS131E08 supports a single +5V power supply as shown in figure 66 in the ADS131E08 datasheet, however you will have to do a level shift to shift your +/-3.3V bipolar input signal to a unipolar signal between 0~+5V, an operational amplifier can be used for this purpose. And then you can use pseudo-differential configuration to drive the ADS131E08 analog inputs, see figure 19 in the datasheet. Pseudo-differential configuration can be done by applying the shifted signal to AINxP pin and providing an external or internal DC bias voltage to AINxN pin,  the figure 59 in the datasheet shows an example of voltage sensing for single-ended Input with the internal bias voltage.

    BR,

    Dale