Current-Limited Switch for Single USB Port

The MAX1931 is a current-limited, 60mΩ switch with built-in fault blanking. Its accurate preset current limit of 0.64A to 1.06A makes it ideally suited for USB applications. The device's low quiescent supply current (14µA) and shutdown current (1µA) conserve battery power in portable applications. The MAX1931 operates with inputs from 2.7V to 5.5V, making it ideal for both 3V and 5V systems.

A fault signal notifies the microprocessor that the internal current limit has been reached. A 10ms fault-blanking feature allows momentary faults (such as those caused when hot-swapping into a capacitive load) to be ignored, thus preventing false alarms to the host system. This fault blanking also prevents a fault signal from being issued when the device is powering up.

In the MAX1931, an output overcurrent condition causes the switch to current limit at 0.64A to 1.06A and active-low FAULT to go low after the 10ms blanking period. When the overcurrent condition is removed, active-low FAULT returns to its high-impedance state.

The MAX1931 has several safety features to ensure that the USB port is protected. Built-in thermal overload protection limits power dissipation and junction temperatures. The device has an accurate internal current-limiting circuitry to protect the input supply against overload. The MAX1931 is available in a space-saving 10-pin µMAX package.

Applications

* Battery Chargers * Docking Stations * Hot Plug-In Power Supplies * Notebook Computers * Portable Equipment * USB Ports and Hubs