Single-cell Li-Ion charger with USB interface
The MAX1555EZK+T is a dedicated single-cell lithium-ion battery charger IC from Analog Devices, designed to draw power from a USB port or a DC supply. It integrates the charge-control and termination logic into a compact TSOT-23-5 package, making it a space-efficient choice for portable devices that charge from a USB cable. The charge current is limited to 340 mA maximum, which aligns with the standard USB 2.0 downstream port's 500 mA budget — the IC's own overhead leaves margin for the system load. The battery regulation voltage is 4.2 V, the typical termination voltage for a single Li-ion cell.
Housed in a SOT-23-5 Thin / TSOT-23-5 package (Analog Devices supplier device package TSOT-23-5), the IC occupies minimal PCB area. The maximum supply voltage is 7 V — nominal is not absolute max; the input rail should be kept below 7 V at all times, including transients.
It is ROHS3 compliant, meeting the current EU restriction-of-hazardous-substances directive.