What this battery monitor does and where it fits
The Maxim Integrated DS2781E+T&R is a battery monitor IC designed for 1 to 2 series-connected Lithium Ion or Lithium Polymer cells. It communicates over a 1-Wire interface, which keeps the BOM simple — a single data line plus ground to the host microcontroller. The device is packaged in an 8-TSSOP (4.40 mm width) for surface-mount assembly and is rated for the -20°C to 70°C ambient temperature range, covering most portable consumer and industrial battery-pack applications.
Cell count and chemistry — fit for a 2S pack
The DS2781E+T&R supports 1 or 2 cells in series. That means it can monitor a single-cell Li-Ion pouch or a 2S (two-series) pack, which is the common configuration for higher-voltage portable tools, medical devices, and backup battery units. The chemistry is specified for Lithium Ion and Lithium Polymer, so it handles the standard 3.6 V / 3.7 V nominal chemistries. If your design uses a different chemistry (LiFePO4, NiMH, lead-acid), this part is not the right fit.
1-Wire interface — what it means for the system
The 1-Wire interface is a single-pin serial bus that carries both data and power (parasitic or external supply). For the DS2781E+T&R, this means the host microcontroller only needs one GPIO pin and a pull-up resistor to read voltage, current, temperature, and accumulated charge data. It simplifies isolation if the battery pack is on a separate ground reference, and it reduces connector pin count. The trade-off is bus speed — 1-Wire tops out around 15-16 kbps in overdrive mode, which is fine for periodic monitoring but not for streaming data.
Package and assembly
The DS2781E+T&R comes in an 8-TSSOP package (4.40 mm body width, 0.65 mm pitch). It is a surface-mount part, so standard reflow soldering applies. The tape-and-reel option (TR suffix) is the production-friendly format for pick-and-place. The package is small enough for space-constrained battery-pack PCBs but still hand-solderable with care.
Lifecycle and compliance
The DS2781E+T&R is listed as Active in production. It is also ROHS3 compliant, so it meets the current EU restriction requirements.