Current-limiting switches increase USB port protection for high power densities

April 23, 2013 // By Paul Buckley
Diodes Incorporated has introduced a family of current-limited power switches offering high current handling in an ultra-small (2 x 2 mm) package.

The new power switches enable power density to be increased in the protection of multiple USB3.0 ports used in applications such as set-top boxes, LED TVs and notebook computers. The six new single-channel devices introduced have an on-resistance of 70 mOhms, cover maximum continuous output currents up to 2.5A and occupy the miniature footprint U-DFN2020-6 package.

For any applications subject to heavy capacitive loads and a possibility of short circuit, the switches provide a robust port protection solution, comprising reverse-current blocking, over-current, over-temperature, under-voltage lockout and short-circuit protection. All devices also integrate an output discharge function to ensure controlled discharging of the output capacitor. In addition, the switches' fast short-circuit response time of 2 µsec prevents any unnecessary system shutdown or restart.

With an input voltage range of 2.7 V to 5.5 V, all devices are suited for 3.3 V and 5 V rail systems in a variety of product designs. Supporting a maximum continuous output current of 2.5A, the AP2501 and AP2511 are, respectively, active-low and active-high enabled and are footprint-compatible with the AP2301 and AP2311 devices handling a 2A continuous output current.

The AP2401 and AP2411 are also 2A rated power switches but provide in addition an output latch-off function that responds to an over current excursion, enabling alternative fault behaviour management. All six power switches also feature an open-drain, over-current fault flag with a 7 msec deglitch time to prevent false reporting.

As well as the U-DFN2020-6 package, the devices are also offered in SO8, MSOP-8/EP and U-DFN3030-8 package options. Ambient operating temperature range is -40C to +85C.