How to improve the conducted immunity (CS) of an electrical force measurement switch (PMS)?

The conducted immunity (CS) of a power supply system (PSS) refers to its resistance to radio frequency interference injected into power and signal ports, according to the IEC 61000-4-6 standard. The key to improving CS lies in constructing low-impedance bypass paths and enhancing the common-mode rejection capability of the circuitry. For power ports, a common-mode inductor CMZ1211-501T combined with a Y capacitor (2.2nF/Y1) is placed at the entry point to provide a low-impedance path to ground for interference currents from 150kHz to 80MHz. At the board level, high-quality decoupling capacitors (0.1μF ceramic capacitor + 10μF tantalum capacitor) are placed near the power pins of each IC. For signal ports, a common-mode inductor CML3225A-510T is used, with a small capacitor (e.g., 100pF) connected in parallel between the signal line and ground. All filtering components must be grounded with low impedance, using a wide and short ground wire connected to a complete ground plane. On the PCB layout, avoid front-to-back coupling of the filtering circuit traces. On the software side, digital filtering is applied to susceptible analog samples. Through comprehensive measures, the CS immunity of PMS can reach 10V (root mean square value), and there will be no performance degradation or malfunction under interference.