The following is 4 x 25W quad audio amplifier circuit (amplifier with four inputs and four outputs) based TDA7381. This amplifier is designed for car audio system, but you can also use this circuit for other purposes. This circuit has a design very simple and very easy to build.
Schematic diagram:
If properly layouted and hooked to standard car radio speakers, the TDA7381 will be intrinsically stable with no need of external compensations such as output R-C cells. Due to the high number of channels involved, this translates into a very remarkable components saving if compared to similar devices on the market.
To simplify pc-board layout designs, each amplifier stage has its own power ground externally accessible (pins 2,8,18,24) and one supply voltage pin for each couple of them.
Top layout / component placement:
About TDA7381:
The TDA7381 is a class AB audio power amplifier in Flexiwatt25 package designed for car radio applications. You may use the circuit for another application such as mp3 player, computer etc. Thanks to the fully complementary PNP/NPN output configuration the TDA7381 allows a rail to rail output voltage swing with no need of bootstrap capacitors..
The extremely reduced components count allows very compact sets. The on-board clipping detector simplifies gain compression operations. The fault diagnostics makes it possible to detect mistakes during Car- Radio assembly and wiring in the car
Download the TDA7381 Datasheet PDF. All information about this circuit is provided in the datasheet.
TDA7381 Datasheet PDF 609.10 KB
Download Datasheet