The SN65220 is a single transient voltage suppressor designed to provide electrical noise transient protection to universal serial bus (USB) 1.1 ports. Note that the input capacitance of the device makes it unsuitable for high-speed USB 2.0 applications. Any cabled I/O can be subjected to electrical noise transients from various sources. These noise transients can cause damage to the USB transceiver and/or the USB ASIC if they are of sufficient magnitude and duration. USB ports are typically implemented in 3-V or 5-V digital CMOS with limited ESD protection. The SN65220 can significantly increase the port ESD protection level and reduce the risk of damage to the circuits of the USB port. The IEC1000-4-2 ESD performance of the SN65220 is measured at the system level. Therefore, system design impacts the results of these tests. A high compliance level may be attained with proper board design and layout.