LM3420AM5X-4.2

Description
The LM3420 series of controllers are monolithic integrated circuits designed for charging and end-of-charge control for Lithium-Ion rechargeable batteries.
The LM3420 is available in five fixed voltage versions for one through four cell charger applications (4.2V, 8.2V/8.4V, 12.6V and 16.8V respectively). Included in a very small package is an (internally compensated) op amp, a bandgap reference, an NPN output transistor, and voltage setting resistors.
The amplifier’s inverting input is externally accessible for loop frequency compensation.
The output is an open-emitter NPN transistor capable of driving up to 15 mA of output current into external circuitry. A trimmed precision bandgap reference utilizes temperature drift curvature correction for excellent voltage stability over the operating temperature range. Available with an initial tolerance of 0.5% for the A grade version, and 1% for the standard version, the LM3420 allows for precision end-ofcharge control for Lithium-Ion rechargeable batteries.  
The LM3420 is available in a sub-miniature 5-lead SOT23-5 surface mount package thus allowing very compact designs.  
Features · Voltage options for charging 1, 2, 3 or 4 cells· Tiny SOT23-5 package· Precision (0.5%) end-of-charge control· Drive capability for external power stage· Low quiescent current, 85 µA (typ.)   Applications · Lithium-Ion battery charging· Suitable for linear and switching regulator charger designs