How to filter out noise from the I/O module's AO output?

Filtering noise from the analog output channels of I/O modules requires multi-dimensional treatment, addressing the source, path, and port. The power supply pins of the output driver chip must be deeply decoupled, using a 10μF tantalum capacitor in parallel with multiple 0.1μF and 0.01μF MLCC capacitors to cover the noise spectrum from low to high frequencies. Connecting a ferrite bead in series at the output, such as the PBZ1608E600Z0T, can effectively suppress the propagation of high-frequency switching noise generated by the chip itself. For voltage output AOs, connecting an RC filter network in parallel between the output and ground, with a resistance of approximately tens of ohms and a capacitance between 1nF and 100nF, can filter out noise in specific frequency bands. For current output AOs, connecting a small inductor or ferrite bead in series in the output loop suppresses high-frequency components. All analog output lines must use shielded twisted-pair cables, with the shield grounded at a single point on the module to avoid noise introduced by ground loops. In PCB design, the grounding of the AO section should use a separate quiet ground plane and be connected to the digital ground at a single point through a 0-ohm resistor or ferrite bead to achieve noise isolation.