Audiophile amplifier offers 0.00003% THD+N
By Paul Rako, Technical Editor -- EDN, September 28, 2006
National Semiconductor, long a major player in the audio market, revisits that arena with the high-voltage, high-performance LM4562 dual audio op amp. The device operates from 5 to 34V, and THD+N (total harmonic distortion plus noise) is 0.00003%. It has an equivalent-input-voltage noise of 2.7 nV/
and a 1/f corner of 60 Hz. The device drives 45 mA and features output-short-circuit and thermal-shutdown protection. The product's bias current is only 10 nA, and bandwidth is 6 MHz. The LM4562 comes in SOIC, DIP, and hermetic-metal-can packages for $2.35, $2.65, and $9.95 (1000), respectively.
The LM4562 complements the recently released LM4702, which will drive high-voltage transistors to create a 150V audio driver, and the company plans units that will operate from 170V. You can create a 300W/channel audio amplifier by adding a couple of power transistors. The LM4702A sells for $24.95 (100), and the LM4702B sells for $150 (25) and will be available by early 2007.
