LM4667 Datasheet | National Semiconductor

Description The LM4667 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 LM4667 processes analog inputs with a delta-sigma modulation technique that lowers output noise and THD when pared to conventional pulse width modulators. The LM4667 is designed to meet the demands of mobile phones and other portable munication devices. Operating on a single 3V supply, it is capable of driving 8Ω transducer loads at a continuous average output of 450m W with less than 1%THD+N. Its flexible power supply requirements allow operation from 2.7V to 5.5V. The LM4667 has high efficiency with an 8Ω transducer load pared to a typical Class AB amplifier. With a 3V supply, the IC’s efficiency for a 100m W power level is 74%, reaching 84% at 450m W output power. The LM4667 features a low-power consumption shutdown mode. Shutdown may be enabled by driving the Shutdown pin to a logic low (GND). The LM4667 has fixed selectable gain of either 6d B or 12d B. The LM4667 has short circuit protection against a short from the outputs to VDD, GND, or across the outputs. Key Specifications j Efficiency at 3V, 100m W into 8Ω transducer 74% (typ) j Efficiency at 3V, 450m W into 8Ω transducer 84% (typ) j Efficiency at 5V, 1W into 8Ω transducer j Total quiescent power supply current j Total shutdown power supply current j Single supply range 86% (typ) 3.5m A (typ) 0.01µA (typ) 2.7V to 5.5V Features n n n n n n n n No output filter required for inductive transducers Selectable gain of 6d B or 12d B Very fast turn on time: 5ms (typ) Minimum external ponents "Click and pop" suppression circuitry Micro-power shutdown mode Short circuit protection Available in space-saving micro SMD and MSOP packages Applications n Mobile phones n PDAs n Portable electronic...