The LM3543 is a three-layer high-side power switch and is an excellent choice for use with rooted, self-powered and bus-powered USB (Universal Serial Bus) hubs. Independent ports enable, flag signals, alert the USB controller under error conditions, initiate control of hot-plug events, and short-circuit protection all compliant with USB specification requirements. The LM3543 accepts input voltages between 2.7V and 5.5V. The enable logic input, available in an active high active low version, can be powered off at any voltage in the range of 2.7V to 5.5V. The continuous LM3543 limits current through a single port to 1.25A (max) when shorted to ground. The low on-state resistance of the LM3543 switch ensures that the LM3543 will meet the USB voltage drop requirements even when the current through the switch reaches 500 mA. Therefore, high power USB functions, low power USB functions, bus powered USB hubs can power down a root or self powered USB hub containing the LM3543. Value-added features of the LM3543 include current foldback to reduce power dissipation in current overload situations, thermal shutdown to prevent high current overheating that can cause device failure, and undervoltage lockout to maintain switching operation if the input voltage falls below acceptable levels.

Features
* 90MW (typ) high-side MOSFET switch
* 500mA continuous current per port
* 7ms failure flag delay to filter hotplug events
* Industry standard pin ordering
*n short circuit protection with power saving current foldback
* Thermal shutdown protection
* Under voltage lockout
* Approved by UL and NEMKO
* Input voltage range: 2.7V to 5.5V
* 5μA, maximum standby supply current
* 16-pin SOIC package
* Ambient temperature range: -40°C to 85°C

application
* USB root, self-powered and bus-powered hubs
* USB devices such as monitors and printers
* General purpose high side switch application