MAX4945

Overvoltage-Protection Controllers with Internal FETProvide Input Voltage Protection Up to +28V without Requiring an External nFET

Description

The MAX4943–MAX4946/MAX4949 family of overvoltage-protection devices feature a low 80mΩ typ RON internal FET and protect low-voltage systems against voltage faults up to +28V. These devices also drive an optional external pFET to protect down to -28V when connected to a load with reverse current protection. When the input voltage exceeds the overvoltage threshold, the internal FET is turned off to prevent damage to the protected components.

All switches feature a minimum 1.2A current-limit protection. During a short-circuit occurrence, the MAX4944B and B place the switch in a latchoff state where the switch turns off and remains off. For the autoretry devices, the switch turns off and continuously checks after a 15ms typ retry time.

The overvoltage thresholds OVLO are preset to 7.4V, 6.35V, 5.8V, 4.56V, or 8.9V. The undervoltage-lockout UVLO thresholds are preset to 2.45V and 4.15V. When the input voltage drops below the undervoltagelockout UVLO threshold, the devices enter a lowcurrent standby mode. See the _Ordering Information/Selector Guide_ in the full data sheet for more details on UVLO/OVLO.

All devices are offered in a small, 8-pin µDFN 2mm x 2mm package and are specified for operation over the -40°C to +85°C temperature range.