LM4681

www.DataSheet4U.com LM4681 10 Watt Stereo CLASS D Audio Power Amplifier with Stereo Headphone Amplifier and I2C/SPI Volume Control March 2006 LM4681 10 Watt Stereo CLASS D Audio Power Amplifier with Stereo Headphone Amplifier and I2C/SPI Volume Control General Description The LM4681 is a fully integrated single supply, CLASS D audio power amplifier solution. The LM4681 utilizes a proprietary balanced pulse-width modulation technique that lowers output noise and THD and improves PSRR when compared to conventional pulse width modulators. The LM4681 also features a stereo headphone amplifier that delivers 80mW into a 32Ω headset with less than 0.5% THD. The LM4681’s I2C/SPI (selectable) volume control has a +30dB to –48dB range when speakers are driven and a range of +13dB to –65dB when headphones are connected. All amplifiers are protected by thermal shutdown. Additionally, the high efficiency power amplifiers have output current limit. With a 8Ω load, the IC’s efficiency for a 6W power level is 85%. The IC features click and pop reduction circuitry that minimizes audible popping during device turn-on and turnoff. The LM4681 is available in a 48-lead LLP package, ideal for portable and desktop computer applications. Key Specifications n n n n n n PO at THD+N =10%, AV = 30dB, VDD = 14V 10W (typ) THD+N at 1kHz at 1W into 8Ω (Power Amp) 0.43% (typ) Efficiency at 7W into 8Ω 85% (min) Total quiescent power supply current 50mA (typ) THD+N 1kHz, 20mW, 32Ω (Headphone) 0.02% (typ) S...