Engineers designing audio equipment for the high-end audiophile or professional recording markets have a limited selection of high-resolution signal amplifiers that will meet end-user demands for both outstanding objective and critical subjective performance. Suitable devices must provide a combination of state-of-the-art specifications for low noise and ultra-low distortion and high GBP, preferably with unity gain stability.


National Semiconductor has developed a series of high-performance, high-fidelity audio amplifiers specifically optimized for these applications. The LME49710 / LM4562 are representative of this line of devices and have been optimized for the high performance and professional community. They provide the designer with unprecedented levels of THD and IM, plus very low noise, and GBWP of 55 MHz with output current of ±26 mA into a 600Ω load. Supply current is extremely low, serving the needs of both portable products and multimedia components utilizing multiple amplifiers. This application note will provide several design examples of high-performance applications using the LME49710/LM4562 that demonstrate their capability in meeting the demands of the highest audible performance.