Stand-Alone ModelGauge m5 Fuel Gauge with SHA-256 Authentication


  • Fuel Gauge IC
  • SHA-256 authentication
  • automatical compensation for cell aging
  • accurate estimation of time-to-empty and time-to-full

The MAX1720x/MAX1721x are ultra-low power stand-alone fuel gauge ICs that implement the Maxim ModelGauge™ m5 algorithm without requiring host interaction for configuration. This feature makes the MAX1720x/MAX1721x excellent pack-side fuel gauges. The MAX17201/MAX17211 monitor a single cell pack. The MAX17205/MAX17215 monitor and balance a 2S or 3S pack or monitor a multiple-series cell pack.

To prevent battery pack cloning, the ICs integrate SHA-256 authentication with a 160-bit secret key. Each IC incorporates a unique 64-bit ID.


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  • ModelGauge m5 Algorithm
    • Eliminates Error when Approaching Empty Voltage
    • Eliminates Coulomb-Counter Drift
    • Current, Temperature, and Age Compensated
    • Does Not Require Empty, Full, or Idle States
    • No Characterization Required for EZ Performance (See the ModelGauge m5 EZ Performance Section)
    • Cycle+ Age Forecasting Observes Lifespan
  • Nonvolatile Memory for Stand-Alone Operation
    • Learned Parameters and History Logging
    • Up to 75 Words Available for User Data
  • Precision Measurement System
    • No Calibration Required
  • Time-to-Empty and Time-to-Full Estimation
  • Temperature Measurement
    • Die Temperature
    • Up to Two External Thermistors
  • Multiple Series Cell Pack Operation
  • Low Quiescent Current
    • MAX172x1: 18µA Active, 9µA Hibernate
    • MAX172x5: 25µA Active, 12µA Hibernate
  • Alert Indicator for Voltage, SOC, Temperature, Current, and 1% SOC Change
  • High-Speed Overcurrent Comparators
  • Predicts Remaining Capacity Under Theoretical Load
  • SHA-256 Authentication
  • Maxim 1-Wire or 2-Wire (I2C) Interface
  • SBS 1.1 Compatible Register Set



  • Handheld devices