LM3420-4.2 Datasheet | National Semiconductor

LM3420-4.2, -8.2, -8.4, -12.6, -16.8 Lithium-Ion Battery Charge Controller July 2000 LM3420-4.2, -8.2, -8.4, -12.6, -16.8 Lithium-Ion Battery Charge Controller General 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 pensated) op amp, a bandgap reference, an NPN output transistor, and voltage setting resistors. The amplifier’s inverting input is externally accessible for loop frequency pensation. The output is an open-emitter NPN transistor capable of driving up to 15 m A 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-of-charge control for Lithium-Ion rechargeable batteries. The LM3420 is available in a sub-miniature 5-lead SOT23-5 surface mount package thus allowing very pact designs. Features n n n n n 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 n Lithium-Ion battery charging n Suitable for linear and switching regulator charger designs Typical Application and Functional Diagram DS012359-1 Typical Constant Current/Constant Voltage Li-Ion Battery Charger DS012359-2 LM3420 Functional Diagram SIMPLE SWITCHER ® is a registered trademark of National Semiconductor Corporation. © 2000 National Semiconductor Corporation DS012359 .national. LM3420-4.2/LM3420-8.2/LM3420-8.4/LM3420-12.6/LM3420-16...