TDA1521 is a dual-channel audio power amplifier integrated circuit, 9-pin single in-line package, output power 2 × 15W. The performance is stable and the sound quality is also good, which is more common in audio applications. TDA1521 can work in single power supply or dual power supply mode, working power supply voltage range 15V ~ 40V (± 7.5-± 20V), the following is the circuit diagram of TDA1521 single power supply connection and dual power supply connection:
Figure 1 TDA1521 single power connection 
Figure 2 TDA1521 dual power connection 
When conditions permit, it is recommended to use dual power supply operating mode, so that the output coupling capacitor (OCL circuit) of the connected speaker can be removed to improve the frequency response.
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