The MAX1666 protects the battery pack in an overcurrent condition by disconnecting the pack from the load at a programmable limit. On-chip power MOSFET drivers control external P-channel MOSFETs to disconnect the cells from external terminals when faults occur. The MAX1666 employs a unique timing scheme that allows three modes of operation for optimal performance and battery power conservation. The MAX1666 can operate in a stand-alone configuration or in conjunction with a microcontroller. It is available in four versions: the S version monitors two Li+ cells, the A and V versions monitor three cells, and the X version monitors four cells. When the charge path is disabled by the charge control pin, the MAX1666A reduces current consumption compared to the MAX1666S/V/X.