If you have high frequency noise/interference, you should use a LP filter between the shunt and INA219.
8.4.1 Filtering and Input Considerations
Measuring current is often noisy, and such noise can be difficult to define. The INA219 offers several options for
filtering by choosing resolution and averaging in the Configuration register. These filtering options can be set
independently for either voltage or current measurement.
The internal ADC is based on a delta-sigma (ΔΣ) front-end with a 500-kHz (±30%) typical sampling rate. This
architecture has good inherent noise rejection; however, transients that occur at or very close to the sampling
rate harmonics can cause problems. Because these signals are at 1 MHz and higher, they can be dealt with by
incorporating filtering at the input of the INA219. The high frequency enables the use of low-value series resistors
on the filter for negligible effects on measurement accuracy. In general, filtering the INA219 input is only
necessary if there are transients at exact harmonics of the 500-kHz (±30%) sampling rate (>1 MHz). Filter using
the lowest possible series resistance and ceramic capacitor. Recommended values are 0.1 to 1 μF. Figure 14
shows the INA219 with an additional filter added at the input.
Statistics: Posted by gmx — Mon Nov 03, 2025 3:47 pm