ADS131M08IPBSR datasheet(89/118 Pages) TI2

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9 Application and Implementation

Note

Information in the following applications sections is not part of the TI component specification, and TI

does not warrant its accuracy or completeness. TI’s customers are responsible for determining

suitability of components for their purposes, as well as validating and testing their design

implementation to confirm system functionality.

9.1 Application Information

9.1.1 Unused Inputs and Outputs

Leave any unused analog inputs floating or connect them to AGND.

Do not float unused digital inputs because excessive power-supply leakage current can result. Tie all unused

digital inputs to the appropriate levels, DVDD or DGND. Leave the DRDY pin unconnected or connect it to

DVDD using a weak pullup resistor if unused.

9.1.2 Antialiasing

An analog low-pass filter is required in front of each of the channel inputs to prevent out-of-band noise and

interferers from coupling into the band of interest. Because the ADS131M08 is a delta-sigma ADC, the

integrated digital filter provides substantial attenuation for frequencies outside of the band of interest up to the

frequencies adjacent to fMOD. Therefore, a single-order RC filter provides sufficient antialiasing protection in the

vast majority of applications.

Choosing the values of the resistor and capacitor depends on the desired cutoff frequency, limiting source

impedance for the ADC inputs, and providing enough instantaneous charge to the ADC input sampling circuit

through the filter capacitor. Figure 9-1 shows the recommended filter component values. These

recommendations are sufficient for CLKIN frequencies between 2 MHz and 8.2 MHz.

10 nF

1 k

To ADC

Inputs

Figure 9-1. Recommended Antialiasing Circuitry

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ADS131M08

SBAS950B – OCTOBER 2019 – REVISED FEBRUARY 2021

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ADS131M08IPBSR Datenblatt(PDF) 89 Page - Texas Instruments