1FEATURES
23• 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 WQFN
Package

APPLICATIONS
• CDMA Phone Handsets
• Low Power Wireless Handsets
• Handheld Information Appliances
• Personal Media Players

DESCRIPTION
The LP3921 is a fully integrated charger and multi-
regulator unit with a fully differential Boomer audio
power amplifier designed 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 suited 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 Audio
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 power 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.