The LTC3337 is a primary battery state of health (SOH) monitor with a built-in precision coulomb counter. It is designed to be placed in series with a primary battery with minimal associated series voltage drop. The patentedinfinite dynamic rangecoulomb counter tallies ALL accumulated battery discharge and stores it in an internal register accessible via an I2C interface. A discharge alarm threshold based on this state of charge (SOC) is programmable. When it is reached, an interrupt is generated at theIRQpin. Coulomb counter accuracy is constant down to no load.The LTC3337 also integrates additional SOH monitoring which measures and reports via I2C: battery voltage, battery impedance, and temperature.To accommodate a wide range of primary battery inputs, the peak input current limit is pin selectable from 5mA to 100mA.Coulombs can be calculated for either the BAT_IN or BAT_OUT pin, determined by the AVCCpin connection.A BAL pin is provided for applications utilizing a stack of two supercapacitors (optional) at the output.The LTC3337 is offered in both 12-lead 2mm × 2mm LFCSP and 16-ball 1.64mm × 1.64mm WLCSP packages.APPLICATIONSLow Power Primary Battery Powered Systems (e.g., 1× LiSOCl2, 2–3× Alkaline)Remote Industrial Sensors (e.g., Meters, Alarms)Asset TrackersElectronic Door LocksKeep-Alive Supplies/Battery BackupSmartMesh®Applications