Product category: Analogue and Mixed Signal ICs
News Release from: National Semiconductor | Subject: LME49600 audio buffer
Edited by the Electronicstalk Editorial Team on 23 January 2008
Buffer keeps noise out of audio
applications
The LME49600 can respond to highly dynamic inputs, accurately reproducing these signals without degrading them by adding distortion.
A new buffer from National Semiconductor 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
This article was originally published on Electronicstalk on 5 Jan 2001 at 8.00am (UK)
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The buffer is well-suited for a wide range of other applications, including line drivers, analogue-to-digital convertor (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 can respond to highly dynamic inputs, accurately reproducing these signals without degrading them by adding distortion.
The device delivers 180MHz bandwidth, a high slew rate of 2000V/us and has 2.6nV/rtHz input referred voltage noise density.
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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%.
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 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.
The LME49600 is a high-performance, low-distortion, high-fidelity audio headphone buffer that can continuously source or sink 250mA.
Designed for use inside an op amp's feedback loop, it increases output current, improves capacitive load drive and eliminates thermal feedback.
The LME49600 offers pin-selectable bandwidth, including a low-current, 110MHz bandwidth-mode that consumes 8mA and a wide 180MHz bandwidth-mode that consumes 15mA.
In both modes, the LME49600 has a nominal 2000V/us slew rate.
Bandwidth is easily adjusted by either leaving the bandwidth-control pin unconnected or connecting a resistor between the bandwidth pin and the emitter voltage pin.
The device's supply voltage range is +/-2.25 to +/-18V.
The LME49600 is fully protected through internal current limit and a thermal shutdown that activates when the junction temperature exceeds 150C.
The LME49600 is available now in a five-lead TO-263 surface mount package.
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