Maxim Integrated's MAX20361 is a fully-integrated solution for harvesting energy from single-/multi-cell solar sources. It has an ultra-low quiescent current (360 nA) boost converter that can start from input voltages as low as 225 mV (typical). To maximize the power extracted from the source, the MAX20361 implements a proprietary maximum power point tracking (MPPT) technique that allows efficient harvesting from 15 μW to over 300 mW of available input power. The MAX20361 also features an integrated charging and protection circuit that is optimized for Li-ion batteries but can also be used to charge supercapacitors, thin-film batteries, or traditional capacitors. The charger features a programmable charging cut-off voltage with thresholds programmable through I²C interface as well as temperature shutoff. The MAX20361 is available in a 12-bump, 0.4 mm pitch, 1.63 mm x 1.23 mm wafer-level package (WLP).