TPA3116 + MH-M18 class D audio amplifier with Bluetooth

TPA3116 + MH-M18 class d audio amplifier with Bluetooth

The TPA3116 + MH-M18 Class D audio amplifier is a powerful and efficient audio amplifier that utilizes the TPA3116 chip. This Class D amplifier is designed to provide high output power while maintaining a compact size. With its high efficiency, it can deliver excellent audio quality while minimizing power consumption. The inclusion of Bluetooth connectivity allows for easy wireless audio streaming, adding convenience to the amplifier’s functionality. Overall, the TPA3116 + MH-M18 Class D audio amplifier is a reliable and versatile option for those looking to enhance their audio experience with powerful and high-quality sound output.

Schematic TPA3116 + MH-M18 class D audio amplifier with Bluetooth




There are some problems with the heat sink that are worth noting it down:

The heat sink on the picture is a 25×25 mm aluminum heat sink. It has good thermal performance (temperature never exceeds 50° on full power), but the size of the heat sink is a little too big. To solve this problem, I pushed two inductors in the middle a little backward to fit the heat sink in. Another alternative solution is to use a 20×25 mm heat sink, which can fit perfectly, and it works fine when the output is below 40W. 40W output can be pretty loud for indoor use, and I would recommend using the alternative solution when it comes to the choice of heat sink.

Design specification:

  • Class D amplifier using TPA3116 IC
  • 50W output (4 Ω load) with 24V DC input power
  • Adjustable gain and oscillation frequency Gain from 0-40dB
  • 400kHz, 500kHz, 1000kHz and 1200kHz adjustable oscillation frequency
  • Small and compact design (62×55 mm)
  • Bluetooth and auxiliary (3.5 mm) input available

Gain and oscillation frequency adjustment:

Gain can be adjusted by turning the potentiometer R3, the reference table is shown below:

R3(Ω) 5.6k 20k 39k
R5 (Ω) NC 100k 100k
Gain (dB) 20 26 32

The frequency adjustment is done by adjusting the connection on AM0, AM1 and AM2. Normally, there is nothing connected to these slot, which will give 400kHz of oscillation frequency. The frequency adjustment is shown on the table below (1=connected with 0 Ω resistor, 0=NC)

AM1 0 0 0 1
AM2 0 0 1 0
AM3 0 1 0 0
Frequency (kHz) 400 500 1000 1200


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BOM TPA3116D2 + MH-M18 class D audio amplifier with Bluetooth

Name Designator Description Quantity
0R AM0,AM1,AM2,JP4,JP7 0603 5
100K R1,R2,R5,R7,R8,R9,R10,R11,R12 0603 9
100K (104) R3 CT-94EW 100K — Trimpot 1
20K R4,R6 0603 2
3.3R (3R3) R13,R14,R15,R16 1206 4
10K (103) R17 0603 1
4.7K R18 0603 1
50K (503) RW1 RK097 Double potentiometer 1
0.1u C1,C2,C3,C4,C8,C11,C30,C32 0603 8
1u C5,C6,C13,C14,C15,C16,C17,C18,C19,C20,C29 0603 11
1nF C7,C12 0603 2
2200uF/35V C9,C10 Electrolytic capacitor 2
1u C21,C22,C23,C24,C25,C26,C27,C28 1206 8
4.7pf C31 0603 1
ORH-G36G LED1 LED 0603 Green 1
MMBT2222A Q1 40V 300mW 600mA NPN SOT-23-3 Bipolar Transistor 1
MH-M18 H1 Bluetooth Module MH M18 1
TPA3116D2DADR U1* 50Wx2@4 Ω D — HTSSOP-32-6.1 mm Audio Power OpAmps 1
LM7805 U2 TO-220-3 — 5V Voltage Regulator 1
10uH (100) L1,L2,L3,L4 10uH SMD,12×12 mm Power Inductor >= 4A 4
100uH (101) L5 L0603 1
Right Speaker SPK1 1×2P 5.08 mm Screw terminal 1
Left Speaker SPK2 1×2P 5.08 mm Screw terminal 1
3.5 mm Audio CN1 PJ-3270-4A — 3.5 mm headphone jack 1
DC-005A-20A DC1 DC-005A-20A — Right-Angle DC Power Receptacle 1
PZ254V-11-01P FALTZ, GND, SYNC 2.54 mm Pin Header 3
TS-1101-C-W SW1 TS-1101-C-W — Brick nogging SPST SMD Tactile Switches 1
SS-12D10L3 SW2 SS-12D10L3 — SPDT Slide Switches 1
SK-3245D-02-L1 SW4 SK-3245D-02-L1 — SPDT Slide Switches 1

*TPA3118D2 and TPA3130D2 can be used

Download files, links, and notes

Download PCB in Gerber, PDF, PNG, SVG



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About the author blog author. Electronics technician for the technical school of Brasilia - Brazil. Interested in electronics, circuits and technology in general.

2 thoughts on “TPA3116 + MH-M18 class D audio amplifier with Bluetooth”

  1. I am confused about the classification of A, B, AB, D amplifiers: common emitter, common base, common collector
    Where does each of them fit in?

    • The classification of amplifiers you mentioned, A, B, AB, and D, refers to different amplifier classes based on their output characteristics. These classes are not directly related to the common emitter, common base, and common collector configurations.

      The common emitter, common base, and common collector are different transistor amplifier configurations commonly used in analog electronics. They define how the transistor is connected to the input and output circuits of the amplifier.

      On the other hand, amplifier classes (A, B, AB, and D) categorize amplifiers based on their output stage design and the conduction angle of the output devices. Here’s a brief overview:

      1. Class A amplifiers: These amplifiers operate in a mode where the output devices (usually transistors) conduct for the entire input signal cycle. They are known for their high linearity but tend to be less efficient as they dissipate power even when there is no input signal.

      2. Class B amplifiers: These amplifiers use a pair of complementary output devices (e.g., NPN and PNP transistors) that conduct during opposite halves of the input signal cycle. Class B amplifiers are more efficient than Class A, but they introduce some distortion due to a small overlap region between the conducting devices.

      3. Class AB amplifiers: Class AB amplifiers are a compromise between Class A and Class B. They have a small bias current flowing through the output devices even when there is no input signal. This biasing reduces distortion and crossover distortion present in Class B amplifiers.

      4. Class D amplifiers: Unlike the previous classes, Class D amplifiers use a different approach. They convert the input signal into a series of pulses, which are then amplified by rapidly switching output devices (typically MOSFETs) on and off. This switching action allows Class D amplifiers to achieve high efficiency while sacrificing some linearity.

      To summarize, the common emitter, common base, and common collector configurations represent different ways of connecting transistors in amplifier circuits. On the other hand, amplifier classes (A, B, AB, and D) classify amplifiers based on their output stage design and the conduction angle of the output devices.


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