The LTC4070’s shunt architecture enables unlimited voltage source compatibility. Only an external resistor is required to set the charge current for the device. The battery float voltage settings are pin-selectable to 4.0V, 4.1V, and 4.2V to allow for charging a wide variety of Lithium-Ion/Polymer batteries. Charge current is limited to 50mA internally and may be set up to 500mA with an external PFET. With the addition of an external PFET, the low battery output pin can implement a latch-off function that automatically disconnects the system load from the battery to protect the battery from deep discharge.