The MAX1894/MAX1924 are lithium-ion/lithium-polymer (Li+) battery pack protection ICs for 3 - 4 series Li+ battery packs. The MAX1894/MAX1924 improve useful operating li life+battery monitoring of single-cell voltage and prevent over/undervoltage conditions. The MAX1894/MAX1924 also protect the battery pack against charge current, discharge current and packshort fault conditions. In the event of a fault condition, the control board drives an external P-channel MOSFET, disconnecting the cell from the external terminal pack. External protection MOSFETs are connected in a common source configuration that does not require external pull-up resistors. "The MAX1894/MAX1924 use only one current-sense resistor for protection. All protection thresholds and delays do not require any external components and are trimmed at the factory. If any battery voltage drops below the undervoltage threshold, the MAX1894/MAX1924 disconnect the package load and power supply , to prevent deep discharge packs. The MAX1894/MAX1924 provide a trickle charge function, which provides a low-current path to safely deep discharge, charge packs. The MAX1894/MAX1924 also have two logic-level inputs that can be used by the microcontroller to disable protection MOSFETs and Shutdown Devices." The MAX1894/MAX1924 feature low quiescent current (30µA typ) and ultra-low shutdown current (0.8µA typ) to prevent deep cell discharge. The MAX1894X is a 4-series battery pack design with no protection threshold hysteresis. "The MAX1924V and MAX1924X include 3 hysteresis-4 series packages, respectively.