Overview
The LM4766 is a dual-channel series audio power amplifier with a mute function. It is a high-end monolithic stereo audio power amplifier IC introduced by National Semiconductor (NS). Each channel can deliver 40 W average power into an 8 ohm load with distortion below 0.1%.
Protection and Integration
Within NS's product family, the LM4766 belongs to the "Overture" series. It includes NS's SPIKC protection circuitry, which dynamically monitors and protects the output-stage transistors' safe operating area (SOA). The device provides protection against overvoltage, undervoltage, overload, output shorts (including shorts to ground and to the supply), thermal runaway, and thermal shock, so external protection circuitry is generally not required.
Key Characteristics
At audible frequencies, the LM4766 achieves low distortion and high signal-to-noise performance. For example, it can reach 0.06% distortion and noise at a 30 W output per channel in the audible band.
Typical designs use a +/-18 V supply. For best performance, the power supply rating should be greater than 100 W.
The LM4766 is a full-featured, high-performance audio power amplifier IC.
Specifications
- Operating supply range: +/-10 V to +/-30 V
- Absolute maximum supply: +/-37 V
- Continuous output power (8 ohm): 40 W per channel
- Total harmonic distortion plus noise (THD+N): 0.009% at 30 W × 2 continuous output
- Signal-to-noise ratio (SNR): 112 dB
- Mute attenuation: 115 dB
- Power supply rejection ratio (PSRR): 125 dB
- Gain-bandwidth product (GBWP): 8 MHz
Suitable Applications
The LM4766 is a dual-channel power amplifier IC that requires external audio input and output components to form a complete sound system. Typical applications include:
- Home entertainment systems and home theater speakers
- Personal audio devices such as desktop computer speakers and portable speaker systems
- Commercial venues such as restaurants, bars, and cafés for background music or public-address systems
- Professional audio equipment such as studio monitors and stage sound systems
