Input protection switch has true reverse blocking

Claimed to deliver an industry-leading performance, the AOZ1376, is a Type-C Power Delivery input protection switch from Alpha and Omega Semiconductor (AOS).

The Type-C Power Delivery compliant input protection switch has up to 28V over-voltage protection.  The AOZ1376 is a smart protection switch with reverse current blocking capability intended for applications where internal circuitry requires protection from exposure to high voltages. It offers low RDS(ON) (20mOhm) in a thermally enhanced 3.0 x 3.0mm DFN package. AOS explains that its advanced co-packaging technology combines a high performance IC with protection features and the company’s latest high safe operating area (SOA) MOSFET.

The AOZ1376 is particularly suited for use in notebooks, ultra books, dongles, and docking stations, with Thunderbolt/USB Type-C PD ports.

Typically, USB Type-C sinking applications are protected from a reverse current using a circuit that uses two discrete back to back MOSFETs along with resistors and capacitors to provide basic soft start functionality. This model lacks programmability and protection features, explains AOS. According to AOS, the AOZ1376 overcomes these disadvantages, saving both component count and PCB footprint, and offers a robust protection feature set to increase the reliability of end products using Type-C power delivery.

“The thinner profile, higher power and greater flexibility offered by USB Type-C and USB PD 3.0 standards have prompted many computer manufacturers to drop the barrel jack in favour of USB Type-C ports for charging their notebook and ultra book offerings; and for the best user experience many of these devices allow the laptop to charge from any of the USB Type-C ports,” explains Mehdy Khotan, power IC marketing director at AOS. This makes reverse voltage protection imperative for these devices, he continues, adding that the AOZ1376 is used in the Type-C charging path of such devices. “It not only protects the laptop and its battery from over-voltage and over-current, but it also prevents an unintended reverse current and over-voltage on the opposite port, protecting the laptop’s peripheral devices,” he adds.

The AOZ1376 operates from 3.4 to 22V on V in. Both V in and V out are rated at 28V absolute maximum. The back-to-back switch configuration blocks any current flow between V in and V out pins when the device is disabled or when the device is enabled, but V out is greater than V in. The AOZ1376 offers programmable soft start and comprehensive protection against short-circuit, thermal overload, reverse voltage and over-voltage.  The over-voltage protection threshold is selectable by an external resistor. The internal soft-start circuitry controls the inrush current due to highly capacitive loads, and the slew rate can be adjusted using an external capacitor. The AOZ1376 also features robust ESD of ±8kV on VIN and VOUT pins and ±4kV on all other pins.

The AOZ1376 is immediately available in production quantities with a lead-time of 12 weeks.

http://www.aosmd.com