High power operational amplifier circuit diagram

LM12 is a high-power operational amplifier integrated circuit launched by National Semiconductor (NS), which can reach 150W in 4 ohm domain with distortion of only 0.01%. The power bandwidth is 60KHZ, and the output power can reach 800W when driving reactive load.

The LM12 has the following features: input protection, controlled startup, thermal limiting, cutout, and dynamic safety range protection.

LM12 is a four-pin TO-3 package, as shown in Figure 1. The shell-VCC interface is gold and molybdenum to prevent thermal fatigue. The internal equivalent circuit is shown in Figure 2.

LM12 can output considerable power without any complicated switch design, and can also be connected in parallel or bridged to obtain greater output power. This integrated circuit can be used for power supply, high-voltage regulator, high-performance audio amplifier, XY plotter and other servo control systems. The following figure shows the schematic diagram of the audio power amplifier installed with LM12 recommended by NS for reference.