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MAX14544：28V-Capable, ILIM VBUS Accessory Switch

Protects Against Host Overload Conditions While Allowing Power to be Supplied to Accessory Devices

The MAX14544/MAX14545 are overcurrent detection switches that can provide power to external accessories while preventing the host device from damage due to faulty overload conditions. These analog switches feature a 270mΩ (typ) on-resistance and operate from a +2.3V to +5.5V input voltage range. The selectable current limit of 200mA or 400mA makes them ideal for load-switching applications. The MAX14544 has an autoretry feature, whereas the MAX14545 has a latchoff feature. When the switch is off, OUT can withstand 28V maximum. When the switch is on and a load is connected to the port, a blanking time of 10.5ms ensures that the transient voltage settles down. After this blanking time, if the voltage across the switch is greater than the active-low FLAG assertion voltage, the switch turns off and then an active-low FLAG is issued to the microprocessor. After the retry time, the device recloses for the duration of the blanking time to check if the load current is lower than the limit. The MAX14544 repeats this cycle if the overload condition is present. During the cycle, active-low FLAG remains asserted. The MAX14544 remains on after the overload condition is removed and active-low FLAG deasserts. For the MAX14545, after the blanking time, the switch turns off and then an active-low FLAG is issued to the microprocessor. The switch can be turned on again by cycling the power or the EN input. The MAX14544/MAX14545 have additional safety features that include thermal shutdown protection, reverse-current blocking, and overvoltage protection. The MAX14544/MAX14545 are offered in a space-saving, 8-pin, 2mm x 2mm TDFN package, and operate over the -40°C to +85°C extended temperature range.

Key Features 200mA or 400mA Selectable Current Limit Output Capable of Withstanding +28V Reverse-Current Shutdown Protection +2.3V to +5.5V Input Operation Range Undervoltage Lockout Autoretry or Latchoff Option Thermal Shutdown Protection 0.1µA (typ) Shutdown Current 5µs Fast Current-Limit Detect 8-Pin TDFN (2mm x 2mm) Package -40°C to +85°C Operating Temperature Range

MAX14544, MAX14545: Typical Operating Circuit Applications/Uses Cell Phones Digital Cameras eBook MID MP3 Players PDAs

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