An analog low-pass filter is required in front of each of the ADC channel inputs to prevent out-of-band noise and interferers from coupling into the band of interest. Because the ADS130B02-Q1 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 f_MOD. Therefore, a single-order RC filter with a cutoff frequency set at least two decades below the modulator frequency provides sufficient antialiasing protection in the vast majority of applications. Figure 9-1 shows a typical RC filter that yields a cutoff frequency of f_C = 39.8 kHz, which is generally a good starting point for a design that uses f_MOD = 4.096 MHz.

Applications that only need to measure dc signals can use much lower filter-cutoff frequencies by increasing the resistor or capacitor values. Larger resistor values have the added benefit of limiting the current into the ADC inputs in case of an overvoltage event.

Figure 9-1 Antialias Filter Example