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 highspeed 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 8 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.