EMI issues of universal serial bus and solutions

Universal serial bus (USB) is rapidly replacing the serial port on personal computers (PC). It provides high speed flexible interconnectivity between a PC and its peripherals. It is a low cost solution which supports data transfer rates up to 12 Mbps (USB 1.0) and 480 Mbps (USB 2.0). It also provides 5V supply to the peripheral device. High level of emission was observed in the power supply wires of the USB while a satellite receiver (peripheral) was evaluated for its functionality. On analysis, it was observed that emission from USB can affect the performance of the peripheral unit depending on the sensitivity of peripheral device to the power supply spurious noise. In this paper, the emissions from a typical PC and methods towards improvement of the emissions are analysed. Precautions to be taken whenever any peripheral device is evaluated, for EMI performance, are discussed. USB, even though a powerful interface, should be carefully used for an overall performance of the system in which it is utilized.