Single-cell Li-Ion charge controller with programmable current
The MCP73834T-FCI/MF from Microchip Technology is a linear charge management controller for single-cell Lithium Ion or Lithium Polymer packs, delivering up to 1.1 A charge current with a regulated 4.2 V battery termination voltage. Charge current is programmable via an external resistor, giving the BOM engineer direct control over the charge rate to match cell capacity and thermal budget without changing the IC.
Thermal and package constraints for board integration
Housed in a 10-VFDFN with exposed pad (3x3 mm DFN per supplier device package), the part relies on the PCB copper pour under the pad for heat sinking — the thermal path from the die to the board determines the practical charge current ceiling in a given ambient. Supply voltage max is 6 V, so the input rail must be regulated — a 5 V USB bus or a 5 V regulated wall adapter is typical; unregulated 9-12 V supplies need a pre-regulator.
The part is ROHS3 compliant, suitable for designs requiring lead-free assembly and EU RoHS exemption-free compliance.