Analog Devices Inc./Maxim Integrated

The LTC4050-4.1/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 5µA. 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 0°C to 50°C temperature window.The LTC4050 begins a new charge cycle when a discharged battery is connected to the charger or when the input power is applied. In addition, a new charge cycle is automatically started if the battery remains connected to the charger and the cell voltage drops below 3.88V for 4.1V cells or below 3.98V for 4.2V cells.The LTC4050 is available in the 10-pin MSOP package.ApplicationsCellular PhonesHandheld ComputersCharging Docks and Cradles

The LTC4052 is a complete standalone pulse charger with integrated MOSFET for 1-cell lithium-ion batteries.An external sense resistor provides overcurrent limiting as a safety precaution against a user connecting a wall adapter with the incorrect or no current limit. The internal MOSFET prevents reverse battery current from flowing if the input voltage is shorted to ground, eliminating the need for a blocking diode.As the battery accepts charge and approaches the programmed float voltage, the internal MOSFET begins switching off and on with the duty cycle gradually decreasing as the battery approaches a fully charged condition. A programmable timer terminates the charge cycle. The near end-of-charge C/10 condition is indicated at theCHRGpin when the average charge current falls to one tenth of the wall adapter current. Removing the input voltage puts the LTC4052 into a sleep mode, dropping the battery current drain to less than 1µA.The LTC4052 is available in a tiny 8-pin thermally enhanced MSOP package.ApplicationsHandheld ComputersCellular TelephonesCradle Chargers

The LTC4054L is a complete, constant-current/constant-voltage linear charger for single cell lithium-ion batteries. Its small size and ability to regulate low charge currents make the LTC4054L especially well-suited for portable applications using low capacity rechargeable lithium-ion coin cells. Furthermore, the LTC4054L is specifically designed to work within USB power specifications.No external sense resistor is needed, and no blocking diode is required due to the internal MOSFET architecture. Thermal feedback regulates the charge current to eliminate thermal overdesign. The charge voltage is fixed at 4.2V, and the charge current can be programmed externally with a single resistor. The LTC4054L automatically terminates a charge cycle when the charge current drops to 1/10th the programmed value after the final float voltage is reached.When the input supply (wall adapter or USB supply) is removed, the LTC4054L automatically enters a low current state, dropping the battery drain current to less than 2µA. The LTC4054L can be put into shutdown mode, reducing the supply current to 25µA.Other features include charge current monitor, undervoltage lockout, automatic recharge and a status pin to indicate charge termination and the presence of an input voltage.*U.S. Patent No. 6,522,118Max Charge CurrentTrickle ChargeLTC4054-4.2800mAYesLTC4054X-4.2800mANoLTC4054L-4.2150mAYesApplicationsCharger for Li-Ion Coin Cell BatteriesPortable MP3 Players, Wireless HeadsetsBluetooth ApplicationsMultifunction Wristwatches

The LTC4054 is a complete constant-current/constant-voltage linear charger for single cell lithium-ion batteries. Its ThinSOT package and low external component count make the LTC4054 ideally suited for portable applications. Furthermore, the LTC4054 is specifically designed to work within USB power specifications.No external sense resistor is needed, and no blocking diode is required due to the internal MOSFET architecture. Thermal feedback regulates the charge current to limit the die temperature during high power operation or high ambient temperature. The charge voltage is fixed at 4.2V, and the charge current can be programmed externally with a single resistor. The LTC4054 automatically terminates the charge cycle when the charge current drops to 1/10th the programmed value after the final float voltage is reached.When the input supply (wall adapter or USB supply) is removed, the LTC4054 automatically enters a low current state, dropping the battery drain current to less than 2µA. The LTC4054 can be put into shutdown mode, reducing the supply current to 25µA.Other features include charge current monitor, undervoltage lockout, automatic recharge and a status pin to indicate charge termination and the presence of an input voltage.Max Charge CurrentTrickle ChargeLTC4054-4.2800mAYesLTC4054X-4.2800mANoLTC4054L-4.2150mAYesApplicationsCellular Telephones, PDAs, MP3 PlayersCharging Docks and CradlesBluetooth Applications

The LTC4054L is a complete, constant-current/constant-voltage linear charger for single cell lithium-ion batteries. Its small size and ability to regulate low charge currents make the LTC4054L especially well-suited for portable applications using low capacity rechargeable lithium-ion coin cells. Furthermore, the LTC4054L is specifically designed to work within USB power specifications.No external sense resistor is needed, and no blocking diode is required due to the internal MOSFET architecture. Thermal feedback regulates the charge current to eliminate thermal overdesign. The charge voltage is fixed at 4.2V, and the charge current can be programmed externally with a single resistor. The LTC4054L automatically terminates a charge cycle when the charge current drops to 1/10th the programmed value after the final float voltage is reached.When the input supply (wall adapter or USB supply) is removed, the LTC4054L automatically enters a low current state, dropping the battery drain current to less than 2µA. The LTC4054L can be put into shutdown mode, reducing the supply current to 25µA.Other features include charge current monitor, undervoltage lockout, automatic recharge and a status pin to indicate charge termination and the presence of an input voltage.*U.S. Patent No. 6,522,118Max Charge CurrentTrickle ChargeLTC4054-4.2800mAYesLTC4054X-4.2800mANoLTC4054L-4.2150mAYesApplicationsCharger for Li-Ion Coin Cell BatteriesPortable MP3 Players, Wireless HeadsetsBluetooth ApplicationsMultifunction Wristwatches