RS-232 and RS-485 PCB Layout Application Note MaxLinear Confidential TBD/18 MaxLinear Confidential •293ANR00 www.maxlinear.com • 293ANR00 i RS-232 and RS-485 PCB Layout Application Note Revision History Revision History Document No. Release Date 293ANR00 December 1, 2022 Initial release. Change Description MaxLinear Confidential December 1, 2022 293ANR00 ii RS-232 and RS-485 PCB Layout Application Note Table of Contents Table of Contents Introduction...........................................................................................................................................................................1 General Recommendation ...................................................................................................................................................1 MaxLinear Confidential December 1, 2022 293ANR00 iii RS-232 and RS-485 PCB Layout Application Note List of Figures List of Figures MaxLinear Confidential December 1, 2022 293ANR00 iv RS-232 and RS-485 PCB Layout Application Note Introduction Introduction This document describes recommended printed circuit board (PCB) design and layout practices for RS-232 and RS-485/RS-422 serial transceiver products. The PCB is one of the most important factors that affect device performance, ESD and EMI. The expected PCB design minimizes the system noise and provide shielding between the PCB’s internal circuitry and the external environment. MaxLinear recommends that the PCB layout practices described in this application note apply to the serial products and the entire system PCB design. General Recommendation This section list the tips you can follow for your PCB design. Tip #1: Use power supply decoupling capacitors and place them close to the device supply pin Voltage sources in electronic systems can generate a lot of noise that affects both digital and analog circuits. Analog systems are extremely prone to supply voltage noise. This unwanted noise can distort th