Advanced Li+ Battery-Pack Protectors

Smallest Li+ Protection Solution Also Offers the Most Complete Set of Features

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The MAX1894/MAX1924 are lithium-ion/lithium-polymer (Li+) battery-pack protector ICs for 3- or 4-series Li+ battery packs. The MAX1894/MAX1924 enhance the useful operating life of Li+ batteries by monitoring individual cell voltages and preventing over/undervoltage conditions. The MAX1894/MAX1924 also protect the battery pack against charge current, discharge current, and pack-short fault conditions.

In case of a fault condition, on-board drivers control external P-channel MOSFETs, which disconnect the cells from the pack external terminals. The external protection MOSFETs are connected in a common-source configuration that does not require external pullup resistors. The MAX1894/MAX1924 use only one current-sense resistor to achieve the protection features. All protection thresholds and delays do not require any external components and are trimmed at the factory.

If any cell voltage drops below the undervoltage threshold, the MAX1894/MAX1924 disconnect the pack from the load and power down to prevent deep discharge of the pack. The MAX1894/MAX1924 offer a trickle-charge feature, which provides a low-current path to safely charge a deeply discharged pack. The MAX1894/ MAX1924 also have two logic-level inputs, which can be used by a microcontroller to disable the protection MOSFETs and to put the device in shutdown. The MAX1894/MAX1924 have low quiescent current (30µA typ) and ultra-low shutdown current (0.8µA typ) to prevent deep-cell discharge.

The MAX1894X is designed for 4-series battery packs, without hysteresis on the protection thresholds. The MAX1924V and MAX1924X include hysteresis for the 3- and 4-series packs, respectively.
MAX1894, MAX1924: Pin Configuration MAX1894, MAX1924: Pin Configuration Enlarge+

Key Features

  • Protect Against Cell Overvoltage Factory Programmable Limits from 4V to 4.4V Accurate to ±0.5%
  • Protect Against Cell Undervoltage Factory Programmable Limits from 2V to 3.2V Accurate to ±2.0%
  • Protect Against Charge, Discharge, and Pack- Short Current Faults
  • Automatically Trickle Charges Deeply Discharged Cells
  • Fully Integrated MOSFET Drivers Do Not Require Pullup Resistors
  • 0.8µA (typ) Shutdown Supply Current Prevents Deep Discharge of Cells
  • 30µA (typ) Operating Supply Current
  • 28V (max) Input Voltage
  • Available in Small 16-Pin QSOP Package
  • Applications/Uses

    • 3- or 4-Series Li+ Battery Packs

    See parametric specs for Battery Fuel Gauges, Protectors, and Monitors (52)

    Part NumberFunctionsBattery TypeParameters MeasuredApplicationsBattery ProtectionVSUPPLY
    Package/PinsOper. Temp.
    MAX1924 Protector3-4 Cell Li-Ion
    Over/Under Voltage
    -40 to +85

    Pricing Notes:
    This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.
    Request Reliability Report for: MAX1924 
    Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C   Material Composition  

    Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

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