The ICs control the charging sequence from the prequalification state through constant current fast-charge, top-off charge, and full-charge indication. Proprietary thermal-regulation circuitry limits the die temperature during fast-charging or when the ICs are exposed to high ambient temperatures, allowing maximum charging current without damaging the ICs. The MAX8845Z/MAX8845Y achieve high flexibility by providing adjustable fast-charge currents (SETI) and an adjustable top-off current threshold (MIN) through external resistors. The MAX8845Z/ MAX8845Y feature a booting assistant circuit that distinguishes input sources and battery connection and provides an enable signal (ABO--MAX8845Z and ABO--MAX8845Y) for system booting. The MAX8845Z/MAX8845Y also integrate an overvoltage-protected output (SAFEOUT) for low voltage-rated USB or charger inputs in system, and a battery-pack detection circuit (DETBAT) that disables the charger when the battery pack is absent. Other features include an active-low control input (EN), an active-low input power source detection output ( POK ), and a fully charged top-off threshold detection output (CHG). The MAX8845Z/MAX8845Y accept an input supply range from 4.25V to 28V, but disables charging if the supply voltage exceeds +7.5V to protect against unqualified or faulty AC adapters. The IC's operate over the extended temperature range (-40C to +85C) and are available in a compact 12-pin, thermally enhanced thin QFN, 3mm x 3mm package (0.8mm max height).