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
