The MAX4838A/MAX4840A/MAX4842AELT 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/MAX4842AELT 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 MAX4842AELT has a 4.7V overvoltage threshold. The MAX4838A/MAX4840A have an undervoltage lockout (UVLO) threshold of 3.25V while the MAX4842AELT 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/MAX4842AELT 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. 
Feature
 
 
  
  - Overvoltage Protection Up to +28V 
 
  - Preset 7.4V or 5.8V Overvoltage Trip Level 
 
  - Drives 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 and μDFN packages 
 
  - Lead-Free 
 
 
 
  
Applications
 
 
 
  - Cell Phones
 
  - Digital Still Cameras
 
  - MP3 Players
 
  - PDAs and Palmtop Devices