56W Audio Power Amplifier Using LM3875
The LM3875 is a high-performance audio power amplifier capable of delivering 56W of continuous average power to an 8Ω load with 0.1% THD+N from 20Hz to 20kHz. The performance of the LM3875, utilizing its Self Peak Instantaneous Temperature (°Ke) (SPiKe™) protection circuitry, puts it in a class above discrete and hybrid amplifiers by providing an inherently, dynamically protected Safe Operating
Area (SOA). SPiKe protection means that these parts are completely safeguarded at the output against overvoltage, under voltage, overloads, caused by shorts to the supplies, thermal runaway, and instantaneous temperature peaks. The LM3875 maintains an excellent signal-to-noise ratio of greater than 95dB(min) with a typical low noise floor of 2.0μV. It exhibits extremely low THD+N values of 0.06% at the rated output into the rated load over the audio spectrum, and provides excellent linearity with an IMD (SMPTE) typical rating of 0.004%.
Features
- 56W continuous average output power into 8Ω
- 100W instantaneous peak output power capability
- Signal-to-Noise Ratio >95dB (min)
- Output protection from a short to ground or to the
- supplies via internal current limiting circuitry
- Output over-voltage protection against transients from inductive loads
- Supply under-voltage protection, not allowing internal biasing to occur when |V+| + |V−| ≤ 12V, thus eliminating turn-on and turn-off transients
- Wide supply voltage range: |V+| + |V−| = 20V to 60V
- CN3 SUPPLY INPUT
- CN1 AUDIO SIGNAL INPUT
- CN2 VOLUME POTENTIOMETER
- LS1 SPEAKER
