TECH BRIEF ESD Protection USB 1.1 Data Lines ? Computers (desktops and laptops) ? Peripherals (printers, scanners, etc.) USB 1.1 Product ? Handheld devices (PDAs, cell phones, MPEG players, etc.) Circuit Board ? Repeaters and hubs ? Digital still cameras PWR USB 1.1 GND Littelfuse offers two possible solu- tions for USB1.1 data line ESD suppression.The first is a silicon based protection array - the Controller D+ D- SP05xxBAxT family of TVS (Transient Voltage Suppression) Avalanche Diodes. These surface mount devices are ESD rated up to 20kV (air) and 15kV (contact) to the IEC-61000-4-2 model. The second solution is built with Multilayer Varistor technology and includes both the MHS Series for high speed applications and the MLE Series. Both families provide up to 15kV (air) and 8kV (contact) to the IEC- 61000-4-2 model. Figure 1. Simple USB 1.1 circuit diagram (ESD suppressors protect the data lines which have exposure to the outside world. The USB protocol uses 2 data lines). Background The Solutions In order to provide the IC with protection against ESD transients, the use of suppression products is recommended.The suppressors are installed between the data line and the chassis ground (parallel connec- tion) and shunt the ESD transient from the data line to the ground. Universal Serial Bus (USB) products (PCI adapter cards, digital cameras, peripherals, etc.) can be susceptible to ESD events when the cable is disconnected from the data port. The ESD pulse can be