Features • Automatic end-of-charge control • Preset or user adjustable charge current regulation • LED drivers for charging status and fault indication • Battery self-discharge refresh (maintenance) • Overvoltage/overcurrent fault detection and protection • Defective battery pack detection • Charge current boost control for cellular phone applications • Charge interruption control input Description The 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 requiring the use of external precision resistors. The IC controls five charge modes: conditioning, fast, top-off, monitor and maintenance. In addition, the LM3621 detects and flags defective batteries as well as 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 off-line ac adapter charger. The LM3621 consists of a logic controller, precision bandgap reference, wide bandwidth transconductance error amplifiers, comparators, and an output buffer. The LM3621 is available in a 16-pin SOIC package and is specified over the range of 0°C to 70°C. Key Specification • Tight output voltage accuracy (±0.5% at TA = 25°C) • Two selectable output voltages (4.2V or 4.1V) • Less than 1 µA current drain from fully charged battery • Preconditioning severely discharged cells (0V to 2.55V) Applications • Complete, full function, protected battery charger for coke or graphite anode, single cell Lithium-Ion battery packs • Linear voltage regulator controlled chargers • High efficiency switching regulator controlled chargers • Cost effective wall adapter chargers

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Typical Application click for larger image	Block Diagram *click for larger image
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Datasheet

Title		Size	Date	Other Language
	LM3621 Single Cell Lithium-Ion Battery Charger Controller	377 Kbytes	4-Oct-04	日本語

Featured Application Notes

Title		Size	Date	Other Language
	AN-294: Application Note 294 Special Sample and Hold Techniques	233 Kbytes	4-Oct-04

More Application Notes

Title		Size	Date	Other Language
	AN-87: Application Note 87 Comparing the High Speed Comparators	249 Kbytes	1-Oct-02
	AN-271: Application Note 271 Applying the New CMOS MICRO-DAC	230 Kbytes	4-Oct-04	日本語

Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LM3621M	CS100	1	14211	71	0	898000	4	254809951

Note: The Early Failure Rates (EFR) were calculated as point estimate PPM based on rejects and sample size for EFR. The Long Term Failure Rates were calculated at 60% confidence using the Arrhenius equation at 0.7eV activation energy and derating the assumed stress temperature of 150°C to an application temperature of 55°C.

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Obsolete Versions

Obsolete Part	Alternate Part or Supplier	Source	Last Time Buy Date
LM3621M	LP3941LQ-A	NATIONAL SEMICONDUCTOR	15 Dec 2008
LM3621MX	NONE	NATIONAL SEMICONDUCTOR	16 Nov 2008