LM4664

The LM4664 is a fully integrated single-supply high efficiency switching audio amplifier. It features an innovative modulator that eliminates the LC output filter used with typical switching amplifiers. Eliminating the output filter reduces parts count, simplifies circuit design, and reduces board area. The LM4664 rocesses analog inputs with a delta-sigma modulation technique that lowers output noise and THD when compared to conventional pulse width modulators.

The LM4664 is designed to meet the demands of mobile phones and other portable communication devices. Operating on a single 3V supply, it is capable of driving 8 transducer loads at a continuous average output of 425mW with less than 1%THD+N. Its flexible power supply requirements allow operation from 2.7V to 5.5V.

The LM4664 has high efficiency with an 8 transducer load compared to a typical Class AB amplifier. With a 3V supply, the IC's efficiency for a 100mW power level is 74%, reaching 84% at 425mW output power.

The LM4664 features a low-power consumption shutdown mode. Shutdown may be enabled by driving the Shutdown pin to a logic low (GND).

The LM4664 has fixed selectable gain of either 6dB or 12dB. The LM4664 has short circuit protection against a short from the outputs to VDD, GND, or across the outputs.