LP3921 Datasheet, PDF (1/34 Pages) National Semiconductor (TI) – Battery Charger Management and Regulator Unit with Integrated Boomer® Audio Amplifier

August 26, 2008
LP3921
Battery Charger Management and Regulator Unit with
Integrated Boomer^® Audio Amplifier
General Description
The LP3921 is a fully integrated charger and multi-regulator
unit with a fully differential Boomer audio power amplifier de-
signed for CDMA cellular phones. The LP3921 has a high-
speed serial interface which allows for the integration and
control of a Li-Ion battery charger, 7 low-noise low-dropout
(LDO) voltage regulators and a Boomer audio amplifier.
The Li-Ion charger integrates a power FET, reverse current
blocking diode, sense resistor with current monitor output,
and requires only a few external components. Charging is
thermally regulated to obtain the most efficient charging rate
for a given ambient temperature.
LDO regulators provide high PSRR and low noise ideally suit-
ed for supplying power to both analog and digital loads.
The Boomer Audio Amplifier is capable of delivering 1.1 watts
of continuous average power to an 8Ω BTL load with less than
1% distortion (THD+N). Boomer Audio Power Amplifiers were
designed specifically to provide high quality output power with
a minimal amount of external components. The Boomer Au-
dio Amplifier does not require output coupling capacitors or
bootstrap capacitors, and therefore is ideally suited for mobile
phone and other low voltage applications where minimal pow-
er consumption and part count is the primary requirement.
The Boomer Audio Amplifier contains advanced pop & click
circuitry which eliminates noises during turn-on and turn-off
transitions.
Features
■ ^Charger
— DC adapter or USB input
— Thermally regulated Charge Current
— Under Voltage Lockout
— 50 to 950 mA Programmable Charge Current
■ ^{3.0V to 5.5V Input Voltage Range}
■ ^{Thermal shutdown}
■ ^{I2C-compatible Interface for controlling Charger, LDO}
outputs and enabling Audio output
■ ^LDO's
7 Low-Noise LDO’s
— 2 x 300 mA
— 3 x 150 mA
— 2 x 80 mA
2% (typ.) Output Voltage Accuracy on LDO's
■ ^Audio
— Fully Differential Amplification
— Ability to drive capacitive loads up to 100 pF
— No output coupling capacitors, snubber networks or
bootstrap capacitors required
■ ^{Space- Efficient 32-pin 5 x 5 mm LLP package}
Applications
■ ^{CDMA Phone Handsets}
■ ^{Low Power Wireless Handsets}
■ ^{Handheld Information Appliances}
■ ^{Personal Media Players}
Boomer^® is a registered trademark of National Semiconductor Corporation.
© 2008 National Semiconductor Corporation 300698
www.national.com