Single-cell Li-Ion/Polymer linear charger — 4.1V regulation target
The BQ2057DGKRG4 from Texas Instruments is a linear charge-management IC for single-cell Lithium Ion or Lithium Polymer battery packs, with a fixed regulation voltage of 4.1V. Charge current is programmable via an external sense resistor, making it adaptable to different cell capacities and charge-time targets. The device operates over -20°C to 70°C ambient, which covers handheld instruments, portable medical gear, and consumer electronics that stay indoors or in moderate outdoor conditions.
Obsolete — sourcing through independent distribution
Texas Instruments has classified the BQ2057DGKRG4 as Obsolete. No last-time-buy window remains open from the factory. For BOM lines that still specify this order code, the only channel is the independent surplus market. No official replacement or pin-compatible successor is listed by TI; any alternate must be qualified against the original design's 4.1V regulation and 8-TSSOP footprint.
Package and mounting — 8-TSSOP/MSOP for tight layouts
Surface-mount assembly with standard reflow profiles; the small footprint suits space-constrained single-cell charger designs where board area is at a premium.
