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Battery Power-Up Logic with Overvoltage and Overcurrent Protection

Provide Overvoltage and Overcurrent Protection in Addition to Battery Power-Up Logic

Product Details

Key Features

Simplified Block Diagram

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Key Features

  • Input Overvoltage Protection Up to +28V
  • Preset Overvoltage Protection Trip Level
    6.38V (MAX4919B)
    5.80V (MAX4920B)
    4.65V (MAX4921B)
  • Adapter/Car-Kit Auto-Selector
  • Low-Current Undervoltage Lockout Mode
  • Internal 1.8A (min) Battery Switchover FET
  • Integrated Low-Battery Detect
  • Battery Short-Circuit Protection
  • Low-Cost External nMOS Overvoltage FET
  • 14-Pin TDFN Package (3mm x 3mm)
  • Applications/Uses

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

    Description

    The MAX4919B/MAX4920B/MAX4921B overvoltage protection controllers protect low-voltage systems against high-voltage faults up to +28V. An internal 1.8A (min) pFET with low RON (100mΩ) switches a battery to the load and also protects the battery against short-circuit faults. When a short circuit occurs, the current through the internal pFET is limited for a blanking period. If the short condition is present after the blanking period, the switch is latched off and remains off until one of the input signals (IN, HP_PWR, PWR_ON) is cycled. The pFET is turned on by a logic-high voltage at PWR_HOLD, HP_PWR, PWR_ON, or IN.

    The overvoltage thresholds (OVLO) are preset to +6.38V (MAX4919B), +5.80V (MAX4920B), and +4.65V (MAX4921B). When the input voltage drops below the undervoltage lockout (UVLO) threshold, the devices enter a low-current standby mode. In shutdown mode, the current is reduced to 0.4µA. The MAX4919B/MAX4920B have a +4.27V UVLO threshold, and the MAX4921B has a +2.35V UVLO threshold.

    The MAX4919B/MAX4920B/MAX4921B are offered in a small 14-pin TDFN package (3mm x 3mm) with an exposed paddle and are specified over the extended -40°C to +85°C temperature range.

    Simplified Block Diagram

    MAX4919B, MAX4920B, MAX4921B: Typical Operating Circuit MAX4919B, MAX4920B, MAX4921B: Typical Operating Circuit Zoom icon

    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 .