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Overvoltage-Protection Controllers with Internal FET

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

Product Details

Key Features

Simplified Block Diagram

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Key Features

  • 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

Applications/Uses

  • Cell Phones
  • Digital Still Cameras
  • MP3 Players
  • PDAs and Palmtop Devices

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 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.

Simplified Block Diagram

MAX4943, MAX4944, MAX4944L, MAX4945, MAX4946, MAX4949: Typical Operating Circuit MAX4943, MAX4944, MAX4944L, MAX4945, MAX4946, MAX4949: Typical Operating Circuit Zoom icon

Technical Docs

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .