Single chip audio power amplifier

The OPA 541 chip  produced by Burr-Brown is a power amplifier that can be powered by a maximum power supply of ±40V
and produce a continuous output of a maximum current of 5A. The output current can be adjusted through an external resistor to protect the amplifier
and load and ensure normal operation. OPA541 has two packaging forms, one is a 10-pin plastic package, and the other is a TO-3
sealed package.
    OPA 541 is a power amplifier with better performance. The circuit is shown in Figure 5-106.
When the input level of the audio signal is 1.3V, when powered by a symmetrical 35v power supply, it can provide approximately 60W of power to a load of 80%.
At this time , through Parallel resistors R6 and R7 limit the output current
value (maximum 8. 5A), and can also safely drive a 4n
load to obtain maximum driving power. However,
attention should be paid to the settings of R6 and R7 to ensure that the amplifier
is safely protected in the event of a short circuit. To make the amplifier
work within its safe zone, the current threshold is required to be
1. 8A. Determining the current threshold resistor value Rc, it can be
calculated by the following formula:
  Rci=(0.813/laha) -0.02(n)
  The amplifier has low distortion, THD is less than
0.5%.
    The quiescent current of lC is only ZOmA, and the bandwidth is determined by
C3 Determined to be about 22kHz, the input filters
R2 and C2 are used to reduce IMD (internal modulation distortion)
and reduce the bandwidth to the actual 16.6kHz; the low-end cutoff frequency is determined by R 1 and C 1 , is
6. 6Hz.