Overvoltage-Protection Controllers with Status Flag

The MAX4838A/MAX4840A/MAX4842A are overvoltage protection ICs that protect low-voltage systems against voltages of up to +28V. If the input voltage exceeds the overvoltage trip level, the MAX4838A/MAX4840A/MAX4842A turn off the low-cost external n-channel FET(s) to prevent damage to the protected components. An internal charge pump eliminates the need for external capacitors and drives the FET gate for a simple, robust solution.

The MAX4838A has a 7.4V overvoltage threshold, and the MAX4840A has a 5.8V overvoltage threshold. The MAX4842A has a 4.7V overvoltage threshold. The MAX4838A/MAX4840A have an undervoltage lockout (UVLO) threshold of 3.25V while the MAX4842A has a UVLO of 2.5V. In addition to the single FET configuration, the devices can be configured with back-to-back external FETs to prevent currents from being back-driven into the adapter.

On power-up, the device waits for 50ms before driving GATE high. Active-low FLAG is held low for an additional 50ms after GATE goes high before deasserting. The MAX4838A/MAX4840A/MAX4842A have an open-drain active-low FLAG output. Active-low FLAG output asserts immediately to an overvoltage fault.

Additional features include a ±15kV (HBM) ESD-protected input (when bypassed with a 1µF capacitor) and a shutdown pin (active-low EN) to turn off the device.

All devices are offered in a small 6-pin SC70 package and 6-pin 1.5mm x 1.0mm µDFN packages and are specified over the extended temperature range of -40°C to +85°C.

Applications

* Cell Phones * Digital Still Cameras * MP3 Players * PDAs and Palmtop Devices

* Overvoltage Protection Up to +28V

* Preset 7.4V or 5.8V Overvoltage Trip Level

* Drives Low-Cost nMOS FET

* Internal 50ms Startup Delay

* Internal Charge Pump

* Undervoltage Lockout

* ±15kV ESD-Protected Input

* Voltage Fault Active-Low FLAG Indicator

* 6-Pin SC70 Package and µDFN packages

* Lead-Free