Overvoltage-Protection Controllers with Internal FET

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Provide Input Voltage Protection Up to +28V without Requiring an External nFET

Part Details
  • Input Voltage Protection Up to +28V
  • Integrated nFET Switch
  • Preset Overvoltage Protection Trip Level
    • 7.40V (MAX4943)
    • 6.35V (MAX4944_)
    • 5.80V (MAX4945_)
    • 4.56V (MAX4946)
    • 8.90V (MAX4949)
  • Low-Current Undervoltage-Lockout Mode
  • Short-Circuit Protection (Latchoff/Autoretry)
  • Internal 15ms (typ) Startup Delay and Retry Times
  • Input Voltage Power-Good Logic Output
  • Thermal-Shutdown Protection
  • Small, 8-Pin (2mm x 2mm) µDFN Package
Additional Details
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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 MAX4945B 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.


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