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MAX4840：Overvoltage Protection Controllers with Status FLAG

The MAX4838–MAX4842 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 MAX4838–MAX4842 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 MAX4838/MAX4839 have a 7.4V overvoltage threshold, and the MAX4840/MAX4841 have a 5.8V overvoltage threshold. The MAX4842 has a 4.7V overvoltage threshold. The MAX4838–MAX4841 have an undervoltage lockout (UVLO) threshold of 3.25V while the MAX4842 has a UVLO of 3.0V. 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 MAX4838/MAX4840/MAX4842 have an open-drain active-low FLAG output, and the MAX4839/MAX4841 have a pushpull FLAG output. The active-low FLAG output asserts immediately to an overvoltage fault. Additional features include a 15kV ESD-protected input (when bypassed with a 1µF capacitor) and a shutdown pin (active-low EN) to turn off the device (MAX4838/MAX4840/MAX4842). All devices are offered in a small 6-pin SC70 package and are specified for operation from -40°C to +85°C.

Key Features Overvoltage Protection Up to 28V Preset 7.4V, 5.8V, or 4.7V Overvoltage Trip Level Drive 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

MAX4838, MAX4839, MAX4840, MAX4841: Typical Operating Circuit Applications/Uses Cell Phones Digital Still Cameras MP3 Players PDAs and Palmtop Devices

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