MAX4840A

The MAX4838A/MAX4840A/MAX4842A are overvoltageprotection 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. FLAG is held low for an additional 50ms after GATE goes high before deasserting. The MAX4838A/MAX4840A/MAX4842A have an open-drain FLAG output. The FLAG output asserts immediately to an overvoltage fault.

Additional features of MAX4840A include a ±15kV (HBM) ESD-protected input (when bypassed with a 1F capacitor) and a shutdown pin (EN) to turn off the device.

The MAX4840A is offered in a small 6-pin SC70 and 6-pin 1.5mm x 1.0mm DFN packages and are specified over the -40°C to +85°C extended temperature range.