How to improve the interference immunity of PMS measurement chips for electrical force measurement switches?

Insufficient immunity of measurement chips (such as metering ICs and ADCs) in PMS can lead to output jumps or reference drift under electromagnetic interference. Improving immunity requires comprehensive reinforcement of the power supply, reference, interface, and PCB. For the power supply, separate LC filters (such as PBZ1608E600Z0T+10μF) and LDO regulators should be used for the analog and digital power pins of the chip, with a 0.1μF decoupling capacitor placed near each power pin. The reference voltage (VREF) is crucial; a low-noise, high PSRR reference source (such as REF5025) should be used, and it should be fully decoupled with capacitors (such as 1μF+0.1μF), and covered with a shield if necessary. A 22Ω resistor or a PBZ1005B-501Z0T ferrite bead should be connected in series on the digital interface (SPI) line to reduce edge noise and suppress ringing. On the PCB, a complete ground plane should be maintained under the chip, and the analog section should be surrounded by a ground guard ring. On the software side, digital filtering (such as moving averages) and outlier removal algorithms can be implemented. With reinforcement, the measurement chip can maintain stable output under IEC 61000-4-4 EFT level 4 (4kV) interference, with an error variation of less than 0.1%.