Electronics

LME49600 Accurately Reproduces High-Dynamic Input Signals without Adding Distortion

January 21, 2008 – A new buffer from National Semiconductor Corporation (NYSE: NSM) delivers the industry’s lowest noise and harmonic distortion for professional audio applications. Part of National’s high-fidelity LME™ audio amplifier family, the LME49600 produces the necessary output current to drive multiple low-impedance headphones and the voltage swing to drive several high-impedance headphones. Additionally, the buffer is well-suited for a wide range of other applications, including line drivers, analog-to-digital converter (ADC) input drivers, low-noise and wide-frequency voltage regulators, and it can also drive the headphone amplifier output stage in mixer consoles as well as capacitive loads in low-power audio amplifiers.

The LME49600’s high-fidelity specifications ensure that it can respond to highly dynamic inputs, accurately reproducing these signals without degrading them by adding distortion. The device delivers 180 MHz bandwidth, a high slew rate of 2000 V/us and has 2.6 nV/rtHz input referred voltage noise density. In a closed-loop configuration with National’s LME49710 single operational amplifier (op amp), the total harmonic distortion plus noise (THD+N) is a vanishingly low 0.00003 percent. Combining the LME49600’s +/- 250 mA output current capacity with the LME49710 and an LM4040 low-noise bandgap reference produces a very high-performance, low-noise, wide-bandwidth, audiophile quality, voltage regulator.

National engineers developed the LME49600 using the company’s proprietary VIP3 process technology. The high-voltage, high-performance, complementary bipolar technology, with vertically integrated NPN and PNP transistors, enables larger peak-to-peak output voltage swings that are well-suited for high-voltage requirements in high-end audio applications. Read more...