Device Protects USB 2.0 Against Over Voltage, Over Current, ESD

The NCP362 is the first overvoltage protection device with both integrated current protection and high-speed electrostatic discharge (ESD) protection for USB 2.0 applications, according to its manufacturer. With an on-board power MOSFET that can handle 500 mA, the device, which is placed behind the USB or bottom connector, provides +20-V front end protection for the downstream USB port. Because long cables can induce ringing caused by serial inductance, the NCP362 has been designed to open the VBUS line when the voltage transient exceeds the internal overvoltage threshold, which is internally set to 5.675 V. This threshold can be changed by a metal tweak if needed. In addition, over-current protection is available, opening the internal MOSFET if the downstream VBUS’s load exceeds 750 mA. So the device supports 500 mA (continuous) for the USB ports. This current clamp value can be also adjusted to a lower value to comply with a 100-mA single or dual port. Both protections work at less than 100 ns. The device also offers system-level IEC 61000-4-2 ±15-kV ESD protection. The NCP362xMTBG is available now in a RoHS-compliant 2- by 2.5- by 0.55-mm package. It costs $0.42 each in quantities of 3000. ON SEMICONDUCTOR, Phoenix, AZ. (619) 398-9700.