The Maxim MAX6781LTC+ is a multi-chemistry battery monitor IC designed to supervise two series-connected cells. It handles Li-ion, Li-Poly, NiMH, and NiCd chemistries, making it a general-purpose monitor for portable and backup-power applications. The part comes in a 6-uDFN package measuring 1.5x1 mm, which suits space-constrained PCBs in handheld instruments, medical devices, or industrial battery-backed systems.
Two-cell support is the headline spec: this IC monitors exactly two series cells, so it fits 2S Li-ion packs or 2-cell NiMH stacks. If your design uses a single cell or three or more in series, this part won't work — look for a different cell-count variant.