200-V audio power amp input stages deliver low distortion

National Semiconductor has announced a pair of 200-V mono audio power amplifier input stages claimed to reduce design time and enable amplifier designs with a THD+N as low as 0.00035%. The highly integrated single-chip LME49811 and LME49830 are intended to address high-end consumer and professional audio applications, as well as a wide range of industrial applications where high voltage and low distortion are required.

The devices contain all the essential circuitry required for a high-quality, high-performance power amplifier input stage. According to the company, they save board space and design time by replacing more than 25 discrete components (many of which must be hand selected and matched by the audio system designer) in high-power audio amplifiers, enabling designs with more channels and more power per square-inch of chassis space.

The LME49811 is a mono version of the company's LM4702 stereo driver, and drives Darlington or bipolar power transistors in an amplifier's output stage. It can easily attain slew rates of 40 V/µs, while providing 9 mA output drive current and 100 µV of output voltage noise.

The LME49830 is optimized to drive a wide range of MOSFETs with standard and low threshold voltages. The device has 60 mA of output current capability and provides slew rates of 40 V/µs, and an output voltage noise of 41 µV.

Both devices have an operating voltage range of ±20 V to ±100 V and are capable of driving transistors in an amplifier's output stage to deliver in excess of 500 W single-ended into an 8-Ω load. Other features include a PSRR of 115 dB and thermal shutdown protection.

The LME49811 and LME49830 can be used in the same base circuit design to create multiple power-level solutions up to 1-kW amplifiers by scaling the output stage devices to accommodate for more power dissipation and current drive. When implemented in a complete power amplifier design, the LME49811's THD+N is only 0.00035%, while the LME49830's THD+N is 0.0006%.

Pricing and availability: The LME49811 and LME49830 are available now in 15-lead TO-247 packages and both are priced at $3.33 in 1000-unit quantities.

National Semiconductor , 1-800-272-9959,

Related links:
LME49811 data page
LME49830 data page

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