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USB 2.0 OVP device packs high-speed ESD protection

Posted: 04 May 2009 ?? ?Print Version ?Bookmark and Share

Keywords:overvoltage protection? OVP device? ESD? USB 2.0?

NCP362 OVP device

ON Semiconductor has developed the NCP362, claimed to be the industry's first overvoltage protection (OVP) device with both integrated current protection and high-speed ESD protection for USB 2.0 applications in portable, telecom, consumer and computing systems.

This integrated device significantly improves safety of USB ports by streamlining design in portable electronics by eliminating the need for standalone OVP, overcurrent protection (OCP) and transient voltage suppressor (TVS) components that have!until now!been necessary to protect vulnerable portable devices against electrical surge damage and electronic discharge from host, wall adapters, human body and unsuitable after-market AC/DC adapters.

The new NCP362, which is placed behind the USB or bottom connector, provides 20V front-end protection for the downstream USB port, due to an integrated power MOSFET that can handle 500mA.

Because long cables can induce ringing due to serial inductance in the USB cable, the NCP362 has been designed to open the VBUS line when the voltage transient exceeds the internal overvoltage threshold, which is internally set to 5.675V. This threshold value can be changed by a metal tweak if a different value is needed for a specific application. In addition, OCP is available, opening the internal MOSFET if the downstream VBUS's load exceeds 750mA, supporting 500mA!continuous!for the USB ports. This current clamp value can be also adjusted to a lower value to be compliant to 100mA single port or dual one.

Both protections are very fast!at fewer than 100ns!offering an efficient protection level for the downstream transceiver, battery charger devices or Lithium battery to be charged. In addition, the NCP362 offers system level IEC 61000-4-2 \15kV ESD protection. The part integrates high-speed ESD diodes for data lines (D+ and D-) and TVS for VBUS pin of the USB ports. Due to the very low capacitance of integrated ESD diodes (0.5 pico-farads/pF), this device is compliant with the USB 2.0 protocol. Depending of the selected NCP362x version, VBUS TVS or D+/D- (or both) are integrated in the same package.

The NCP362 is a key addition to the portfolio of ON Semiconductor products targeted at the four primary subsystems typically found in portable applications. This device specifically addresses the challenging requirements within the interconnect subsystem. ON Semiconductor also offers solutions for the display and lighting, power management, and audio/video subsystems for portable devices.

The NCP362xMTBG is now available in a 2mm x 2.5mm x 0.55mm DFN, Pb-free, RoHS compliant package. It is priced at $0.42 per unit in 3,000 quantities.

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