MAX1874

MAX1874 19-2912; Rev 1; 2/07 EVAALVUAAILTAIOBNLEKIT Dual-Input, USB/AC Adapter, 1-Cell Li+ Charger with OVP and Thermal Regulation General Description The MAX1874 charges a single-cell Li+ battery from both USB and AC adapter sources. It also includes battery-to-input power switchover, so the system can be powered directly from the power source rather than from the battery. In its simplest application, the MAX1874 needs no external MOSFET or diodes, and accepts input voltages up to 6.5V; however, DC input overvoltage protection up to 18V can be added with a single SOT PFET. On-chip thermal limiting simplifies printed circuit board (PCB) layout and allows optimum charging rate without the thermal limits imposed by worst-case battery and input voltage. When the MAX1874 thermal limit is reached, the charger does not shut down but simply reduces charging current. Ambient or battery temperature can be monitored with an external thermistor. When the temperature is out of range, chargin...