Chips Guard USB Ports Against ESD Transients

In the USB6B1/2 devices, a diode bridge and integrated Transil diode are configured to protect USB data lines against positive and negative transient overvoltages and to keep the voltage between the power conductors within safe limits. ESD sensitivity of USB ports is a major concern to designers, because the USB controller IC that manages power and directs signal traffic is inherently more vulnerable to ESD than an RS-232 port. The consequences of damage are potentially much more severe, as one USB port may control up to 127 peripherals.The USB6B devices provide up to 15 kV of ESD protection in keeping with IEC1000-4-2 standards. ESD transients appearing on data lines are clamped either to the V_CC supply rail or to ground by the diodes. Pinouts for both devices are directly compatible with that of the USB connector.