FM4057 is a highly integrated and reliable single lithium battery linear charging chip that can use an AC power adapter or USB port as its power input. When the power is removed, FM4057 goes into sleep mode. The FM4057 chip charging system integrates 3 loops: charging constant current, charging constant voltage, and temperature constant loop to provide excellent performance for the charging system.

    The FM4057 optimizes the charging process by using a control algorithm that includes pre-charge mode, fast charge mode and constant voltage mode. When fully charged, it is maintained in constant voltage mode to ensure that the battery is always fully charged. Its charging current can be set by an external resistor with a charging current configuration up to 1A. The internal thermal feedback circuit of the chip adjusts the core temperature to ensure that the battery is charged at the best rate under any available ambient temperature. Simply put, this function is that the chip temperature will rise at the beginning of charging, resulting in a certain decrease in charging current as the temperature increases. When the internal temperature loop reaches stability, the charging current tends to stabilize. Achieve the effect of constant temperature charging. The VIN side of the FM4057 can withstand voltages up to 32V, and it also integrates various protection functions: input overvoltage, input undervoltage, output overvoltage, output short circuit, chip overtemperature.

    FM4057 can be provided in SOT23-6, SOT23-5, ESOP8 and DFN6 package, among which FM4057S adopts SOT23-6 package; FM4057S5 adopts SOT23-5 package; FM4057E adopts ESOP8 package; The FM4057D is packaged in DFN6.