LTC4078X

The LTC4078X is a standalone linear charger that is capable of charging a single-cell Li-Ion/Polymer battery from both wall adapter and USB inputs. The charger can detect power at the inputs and automatically select the appropriate power source for charging.

No external sense resistor or blocking diode of LTC4078X is required for charging due to the internal MOSFET architecture.

The LTC4078X features a maximum 22V rating for both wall adapter and USB inputs, although charging stops if the selected power source exceeds the overvoltage limit. Internal thermal feedback regulates the battery charge current to maintain a constant die temperature during high power operation or high ambient temperature conditions.

The float voltage is fi xed at 4.2V and the charge current is programmed with an external resistor. The LTC4078X terminates the charge cycle when the charge current drops below the programmed termination threshold after the fi nal fl oat voltage is reached.

Other features of LTC4078X include battery present detection, automatic recharge, undervoltage lockout, charge status outputs, and "power present" status outputs to indicate the presence of wall adapter or USB power. The LTC4078X is offered in a low profi le (0.75mm) 3mm * 3mm 10-lead DFN package.