Single-cell Li-ion charger with integrated power-path management
The MAX8903DETI+ is a single-cell Lithium-Ion battery charger from Analog Devices' Smart Power Selector™ series, designed to charge a 4.1V battery pack at up to 2A programmable current. It accepts a USB or DC supply up to 16V and includes over-voltage fault protection, with programmable charge current and timer via external components.
Charge current and battery regulation limits
Maximum charge current is 2A, programmable via an external resistor — this sets the charge rate for a single 4.1V Li-ion cell, so the thermal design of the 28-TQFN package must dissipate the I²R loss at full current. The 16V supply maximum covers USB VBUS (5V nominal) and common 12V wall adapters, with headroom for transients before the over-voltage protection triggers. Programmable timer and current features let the designer tailor the charge profile to the cell capacity — a 1000 mAh cell charges at 0.5C with a 500 mA setting, while a 2000 mAh cell uses the full 2A for 1C rate.