1FEATURES
23• 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

APPLICATIONS
• Cellular Phones
• PDAs
• Digital Cameras
• USB Powered Devices
• Programmable Current Sources

KEY SPECIFICATIONS
• 1% Charger Voltage Accuracy Over
0°C ≤ TJ ≤ 85°C
• 4.3V to 6V Input Voltage Range
• 100 mA to 750 mA Charge Current Range, in
Charger Mode
• 100 mA to 500 mA Charge Current Range, in
USB Mode
• WSON Package Power Dissipation:
2.7W at TA = 25°C

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.