The LTC 4050-4.1/LTC4050-4.2 are complete standalone constant-current/constant-voltage linear charge controllers for lithium-ion (Li-Ion) batteries. Charge current is programmable and final float voltage has 1% accuracy. When the input supply is removed, the LTC4050 automatically enters a low quiescent current sleep mode, dropping the battery drain current to 5A. An internal comparator detects the near-end-of-charge (C/10) condition while a programmable timer, using an external capacitor, sets the total charge time. Fully discharged cells are automatically trickle charged at 10% of the programmed current until cell voltage exceeds 2.49V. The thermistor interface suspends charging if the cell temperature is outside of a 0C to 50C temperature window.