SBASAD2 November 2021 ADS130B04-Q1
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 ADS130B04-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 fMOD. 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 fC = 39.8 kHz, which is generally a good starting point for a design that uses fMOD = 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.