Description
The MAX8845 is a intelligent, stand-alone constant-current, constant-voltage (CCCV), thermally regulated linear chargers designed for charging a single-cell lithium-ion (Li+) battery. The MAX8845 integrate a current-sense circuit, MOSFET pass element, thermal-regulation circuitry, and eliminate the external reverse-blocking Schottky diode to create the simplest and smallest charging solutions for handheld equipment. 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 MAX8845 achieve high flexibility by providing adjustable fastcharge currents (SETI) and an adjustable top-off current threshold (MIN) through external resistors. The MAX8845 feature a booting assistant circuit that distinguishes input sources and battery connection and provides an enable signal (ABO—MAX8845 and ABO— MAX8845) for system booting. The MAX8845 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 MAX8845 accept an input supply range from 4.25V (4.4V for MAX8845 only) to 28V, but disable charging if the supply voltage exceeds +7.5V (+8.0V for MAX8845 only) to protect against unqualified or faulty AC adapters. The ICs operate over the extended temperature range (-40°C to +85°C) and are available in a compact 12-pin, thermally enhanced thin QFN, 3mm x 3mm package (0.8mm max height).
- CCCV, Thermally Regulated Linear 1-Cell Li+ Battery Charger
- No External MOSFET, Reverse Blocking Diode, or Current-Sense Resistor
- Programmable Fast-Charge Currents (1ARMS max)
- Programmable Top-Off Current Threshold (MIN)
- Input Overvoltage Protected 4.7V Output (MAX8845) or 4.85V (MAX8845) (SAFEOUT)
- Proprietary Die Temperature Regulation Control (+115°C)
- 4.25V (4.4V for MAX8845 only) to 28V Input Voltage Range with Input Overvoltage Protection Above +7.5V (+8.0V for MAX8845X only)
- Low-Dropout Voltage (300mV at 500mA)
- Input Power-Source Detection Output (POK), Charge Status Output (CHG), Charge-Enable Input (EN)
- Output for Autobooting (ABO-MAX8845, ABO-MAX8845)
- Tiny, 3mm x 3mm 12-Pin Thin QFN Package, 0.8mm Height (max)
