Features • Supports USB Charging Scheme • Integrated Pass Transistor • Near-Depleted Battery Preconditioning • Monitors Battery Temperature • Built-In 5.6 hour timer • Under Voltage and Over Voltage Lockout • Charge Status Indicators • Charge Current Monitor Analog Output • LDO Mode Operation can source 1 Amp • Continuous Over Current/Temperature Protection Description The LP3947 is a complete charge management system that safely charges and maintains a Li-Ion battery from either USB power source or AC adaptor. In USB mode, the LP3947 supports charging in low power or high power mode. Alternatively, the LP3947 can take charge from AC adaptor. In both USB and AC adaptor modes, charge current, battery regulation voltage, and End of Charge (EOC) point can be selected via I2C interface. The LP3947 can also operate on default values that are pre-programmed in the factory. The battery temperature is monitored continuously at the Ts pin to safeguard against hazardous charging conditions. The charger also has under-voltage and over-voltage protection as well as an internal 5.6 hr timer to protect the battery. The pass transistor and charge current sensing resistor are all integrated inside the LP3947. The LP3947 operates in four modes: pre-qualification, constant current, constant voltage and maintenance modes. There are two open drain outputs for status indication. An internal amplifier readily converts the charge current into a voltage. Also, the charger can operate in an LDO mode providing a maximum of 1.2 Amp to the load. Key Specification • 1% Charger Voltage Accuracy Over 0°C <= TJ <= 85°C • 4.3V to 6.0V Input Voltage Range • 100 mA to 750 mA charge current range, in charger mode • 100mA to 500mA charge current range, in USB mode • LLP Package Power Dissipation: 2.7W at TA = 25°C Applications • Cellular Phones • PDAs • Digital Cameras • USB Powered Devices • Programmable Current Sources

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Datasheet

Title		Size	Date	Other Language
	LP3947 USB/AC Adaptor, Single Cell Li-Ion Battery Charger IC	649 Kbytes	6-Jul-06

Featured Application Notes

Title		Size	Date	Other Language
	AN-1341: Application Note 1341 LP3947 Evaluation Board	584 Kbytes	18-Nov-04

More Application Notes

Title		Size	Date	Other Language
	AN-1296: Application Note 1296 LP3945/LP3946 Evaluation Kit	280 Kbytes	17-Sep-04
	AN-1715: Application Note 1715 LP3943/LP3944 as a GPIO Expander	93 Kbytes	12-Oct-07	中文
	AN-1344: Application Note 1344 LP3944 Evaluation Kit	366 Kbytes	20-Oct-04
	AN-1300: Application Note 1300 LP3943 Evaluation Kit	466 Kbytes	20-Oct-04

Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LP3947ISD-09	CMOS7	0	18406	0	0	1089000	4	309006723
LP3947ISD-51	CMOS7	0	18406	0	0	1089000	4	309006723
LP3947ISDX-51	CMOS7	0	18406	0	0	1089000	4	309006723

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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