LTC4052-4.2 Series

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