Unused, new old stock.
This National Semiconductor LM3621 is a full-function constant voltage, constant current (CVCC) lithium-ion (Li+) battery charger controller. It provides 1% regulation accuracy over the specified temperature range without using external precision resistors.
This 16-pin SOIC IC controls five charge modes: conditioning, fast, top-off, monitor, and maintenance. In addition, the LM3621 detects and flags defective batteries and over-current and over-voltage fault events.
The architecture of the IC is based on high gain constant voltage and constant current control loops. The LM3621 is designed to control a switching charger, a linear charger, or an offline ac adapter charger.
The LM3621 consists of a logic controller, precision bandgap reference, wide bandwidth transconductance error amplifiers, comparators, and an output buffer.