50W class D amplifier based on the MAX9709

My project is a 50W 4Ω class D amplifier with the MAX9709, I decided to carry out this project because many times students find it difficult to work with SMD components, especially with ICs like the one used in this project since their pins are approximately 0.3 mm and it becomes practically impossible to work with a PCB made by hand, I want to carry out this great project and serve as a motivation for all those who want to start working with class D amplifiers in a professional way and with PCB of the best quality, with this PCB that I designed I want to show that working with SMD components is not as difficult as it seems and that hand in hand with the best quality PCBS it becomes quite an adventure.

This amplifier can be used in televisions, HiFi audio, and in portable speakers since due to its high efficiency it will make the most of the energy supplied by, for example, a battery, the supply voltage of this module is from + 10v to + 22v and with a current of 2 to 4 amps depending on the supply voltage.the manufacturer recommends putting a 47uF (C11) capacitor to have optimal filtering at the power source.

This integrated uses two power sources, one of power and the other digital, this is because noises are often found in power sources that can be connected to more circuits, by having two power sources it is possible to isolate the part of power and the digital part of the integrated, reducing to the maximum the possibility of having some type of noise in our amplifier, this configuration is usually used a lot in televisions since they are generally used with high-frequency switched sources, in this case I did not see the need to feed this module with 2 sources since it will not have contact with any other device that could contaminate it, so I decided to put a transistor with a zener diode to regulate the digital voltage that the integrated power supply needs, in In reality, you can use any transistor that is NPN since the current consumed by the digital pins of the integrated is minimal.

what I recommend is to put A small heatsink to the integrated one to prevent overheating that could shorten the useful life of the integrated.

The operation of this amplifier is based on the integrated MAX9709 which is a class D amplifier with a great sound quality easily comparable to that of a class AB amplifier but with a remarkable efficiency of up to 87%, in this design the integrated It will be working in BTL configuration for which it will deliver a power of up to 50W with a THD of 10%, the design consists of a led that will indicate if the amplifier is on or not.

The amplifier consists of two pins which, if bridged, will immediately send the amplifier to MUTE.

This design was made on a two-layer PCB which will provide greater stability for the amplifier and also avoid possible interference.

I want to thank PCBWay for giving me this great opportunity to publicize my projects and at the same time for the support they provide to all students and engineers to fulfill their dreams and make their projects come true.

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Oct 24,2020
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