 |
| Fig. 1 - PCB 68W Hi-Fi Audio Power Amplifier - IC LM3886T |
The LM3886 is a high-performance audio power amplifier capable of delivering 68W of continuous average power to a 4Ω load and 38W into 8Ω with 0.1% THD+N from 20Hz–20kHz.
The performance of the LM3886, utilizing its Self Peak Instantaneous Temperature (°Ke) (SPiKe) protection circuitry, puts it in a class above discrete and hybrid amplifiers by providing an inherently, dynamically protected Safe Operating Area (SOA).
SPiKe protection means that these parts are completely safeguarded at the output against over-voltage, under-voltage, over-loads, including shorts to the supplies, thermal runaway, and instantaneous temperature peaks. The IC pinout is shown in Figure 2 below.
 |
| Fig. 2 - Pinout IC LM3886T |
The LM3886 maintains an excellent signal-to-noise ratio of greater than 92dB with a typical low noise floor of 2.0μV. It exhibits extremely low THD+N values of 0.03% at the rated output into the rated load over the audio spectrum, and provides exceptional linearity with an IMD (SMPTE) typical rating of 0.004%.
You might also be interested in:
- 170W AB Class Bridge Mode Amplifier using TDA7294 IC + PCB
- High Fidelity 14W - 12V Power Amplifier using TDA2030 IC + PCB
- 24W Stereo Hi-Fi Audio Amplifier using TDA2616 + PCB
- HI-FI 120W RMS Amplifier Circuit using LM4780 IC + PCB
- 4 x 50W High Power Amplifier, 14.4V - IC TDA7563A + PCB
- 180W RMS 4-Channel Amplifier with TDA7386 + PCB
- 320W Power Audio Amplifier, Powered with 14.4V - 2Ω with IC TDA7560 + PCB
- 100W RMS Audio Amplifier IC TDA7294 + PCB
- 200W RMS Stereo Power Amplifier with IC STK4231II + PCB
Features
- 68W cont. avg. output power into 4Ω at VCC = ±28V
- 50W cont. avg. output power into 8Ω at VCC = ±35V
- 38W cont. avg. output power into 8Ω at VCC = ±28V
- 135W Instantaneous Peak Output Power Capability
- Signal-to-Noise Ratio ≥ 92dB
- An Input Mute Function
- Output Protection from a Short to Ground or to the Supplies via Internal Current Limiting Circuitry
- Output Over-Voltage Protection against Transients from Inductive Loads
- Supply Under-Voltage Protection, not Allowing Internal Biasing to Occur when |VEE| + |VCC| ≤ 12V, thus Eliminating Turn-On and Turn-Off Transients
- 11-Lead TO-220 Package
The Power Supply
The power supply is Symmetrical, for those who will use a 4Ω Loudspeaker, the 2x 20Vac transformer is recommended, because when rectified, it is around 28Vdc.
And for those who will use it at 8Ω, it is recommended the 2x 25Vac transformer, which when rectified, is 35Vdc on average.
The recommended transformer power is about 120W, this means that the transformer current is on average 3.5 Amperes, for mono, if it's stereo, do the duplication, that is, 8 Amperes.
A good size heat radiator is necessary, since the IC LM3886 works in class AB, there is a great loss in heat at full power, and the recommended filter capacitors is 2 x 10.000uF/50V
The output inductance is formed by 15 turns of enameled wire, with a diameter of approximately 0.5mm, wound around the resistor R8 of 10Ω 1W. The complete schematic diagram is shown in Figure 3 below.
 |
| Fig. 3 - Schematic 68W Hi-Fi Audio Power Amplifier - IC LM3886T |
Components List
- U1 ..........................LM3886 Integrated Circuit
- R1, R3 .................. 2.2K ohms - 1/8W - Resistor - (red, red, red, gold)
- R2, R4, R5, R6 ..... 47K ohms - 1/8W - Resistor - (yellow, violet, orange, gold)
- R7 ......................... 4R7 ohms - 1W - Resistor - (yellow, violet, gold, gold)
- R8 ......................... 10 ohms - 1W - Resistor - (brown, black, brown, gold)
- C1 ......................... 2.2uF - 25V - Electrolytic capacitor
- C2 ......................... 680pF Polyester capacitor
- C3 ......................... 470uF - 50V - Electrolytic capacitor
- C4, C8 .................. 100nF - ceramic/polyester capacitor
- C5, C7 .................. 1000uF - 50V - Electrolytic capacitor
- C6 ......................... 47pF - ceramic/polyester capacitor
- C9 ......................... 220nF - ceramic/polyester capacitor
- C10 ....................... 100uF - 50V - Electrolytic capacitor
- L1 ........................ 0.7uH Inductor - *See Text
- P1, P2 ................... Block 5mm 2 Pin weldable terminal Connector
- P3 ......................... Block 5mm 3 Pin weldable terminal Connector
- Others ................... PCP, Heat Sink, Wires, Solders and Etc.
We are offering the PCI - Printed Circuit Board, in GERBER, PDF and PNG files, for you who want to do the most optimized assembly, either at home.
If you prefer in a company that develops the board, you can is downloading and make the files in the Download option below.
Files to download, Direct Link:
Click on the link beside: GERBER, PDF and PNG files
If you have any questions, suggestions or corrections, please leave them in the comments and we will answer them soon.
Subscribe to our blog!!! Click here - elcircuits.com!!!
My Best Regards!!!
