The MAX4843MAX4846 overvoltage protection controllers protect low-voltage systems against high-voltage faults of up to 28V. When the input voltage exceeds the overvoltage threshold, these devices turn off a 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 overvoltage trip level is set to 7.4V (MAX4843), 6.35V (MAX4844), 5.8V (MAX4845), or 4.65V (MAX4846). When the input voltage drops below the undervoltage lockout (UVLO) threshold, the devices enter a low standby current mode (10A). The MAX4843/MAX4844/ MAX4845 have a UVLO threshold of 4.15V, and the MAX4846 has a UVLO threshold 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.