LM3886 amplifier board #Minimus Gainclone 70W

LM3886 Minimus Power Gainclone

LM3886 amplifier board #Minimus lm3886 gainclone 70W, Gainclone is a circuit compact audio power amplifier using integrated circuit National Semiconductors LM6886TF, PCB compact, making it ideal for use where you need a compact amplifier with high power and high-quality audio.
Ideal for use in various applications such as, computer games, MP3 Player, Home Theater, Surround sound, etc.

About the amplifier circuit with LM3886 – Minimus Power

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 overvoltage, undervoltage, overloads, including shorts to the supplies, thermal runaway, and instantaneous temperature peaks.

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 excellent linearity with an IMD (SMPTE) typical rating of 0.004%.

  • 68W Cont. Avg. Output Power into 4Ω at VCC = ±28V
  • 38W Cont. Avg. Output Power into 8Ω at VCC = ±28V
  • 50W Cont. Avg. Output Power into 8Ω at VCC = ±35V
  • 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
  • Wide Supply Range 20V – 94V

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LM3886 is a single-channel, high-performance audio power amplifier IC produced by National Semiconductor (NS) company  , the maximum continuous output power up to 60W, from the launched time to now, was loved by the majority of audiophiles.

The single-channel power amplifier design, a board per channel amplifier parts, amplifier board can be used in parallel.
Recommend DC dual 20-28V power supply.

  • 68W output power into 4Ω at VCC=±28V
  • 38W output power into 8Ω at VCC=±28V
  • 50W output power into 8Ω at VCC=±35V

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There is an Excel spreadsheet to assist in calculations for amplifiers with the integrated circuits LM1876, LM4765, LM4766, LM4700, LM4701, LM2876, LM3875, LM3876 and LM3886:
Overture Design Guide xls
Using the Overture Design Guide

C1 of 1µF serves to block any DC voltage at the amplifier input and coupling the audio signal, also together with R3 22K, forms a high-pass RC filter, the formula is Fc=1/2ΠRC. In our circuit it will give 7.2 Hz.
R1 and C3 form a low-pass filter, to avoid RF signals at the amplifier input. The formula is Fc=1/2ΠRC, in our circuit this value was 723kHz, if you prefer you can change this.

R5 is the feedback resistor and defines the gain of the amplifier, the formula is Av=1+Rf1/Ri where Rf1 = R5 and Ri = R2, in our case we have a gain of 23V/V or 27dB.

R6 and C5 form a low-pass filter in the feedback circuit.

R7 and C10 form the Zobel network, preventing high-frequency oscillation caused by inductive loads.

The mute circuit has resistor R4, it should be calculated using the following formula ⇒ RM ≤ (|VEE| – 2.6V)/I8 where I8 is ≥ 0.5 mA. VEE is our negative voltage used.

To use the Excel spreadsheet:
Rf = R5
Ri = R2
Ci = C2
Rb = R1
Rin = R3
Cin = C1

Schematic LM3886 amp circuit diagram #Minimus Gainclone 70W

Schematic Lm3886 Amplifier Board Circuit Diagram #Minimus Gainclone 70W

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BOM to assemble LM3886 amp Minimus power

Last Update: 10/11/2021 15:49

Part Value Description Quantity
C1 1µF (105) Polyester Capacitor 1
C2 22µF/50V Electrolytic Capacitor 1
C3 220pF (221) Ceramic Capacitor 1
C4, C9 100n (104) Ceramic Capacitor 2
C10 100n (104) Polyester Capacitor 1
C5 47pF (470) Ceramic Capacitor 1
C6, C7, C8 100µF/50V Electrolytic Capacitor 3
OUT Audio Output Terminal block 2 pin 5.08 mm 1
IN Audio Input Terminal block 2 pin 5.08 mm 1
DC DC power supply Terminal block 2 pin 5.08 mm 1
IC1 LM3886T LM3886TF Audio amplifier integrated circuit 1
Resistors 1/4W
R1, R2 1k Brown, Black, Red, Gold 2
R3, R5, R6 22k Red, Red, Orange, Gold 3
R4 47k Yellow, Violet, Orange, Gold 1
R7 2.7 — 1W Red, Violet, Gold, Gold 1
R8 0.1 — 5W 0.1 ohm 5 Watts Ceramic Resistor 1
Solder, Wires, PCB, case, symmetrical supply, etc.

Download PDF files of this LM3886 Datasheet, PCB top and bottom, schematic, board component view.

Gerber added

Download PDF


Download the Datasheet in PDF and application notes.

Model for simulation

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

5 thoughts on “LM3886 amplifier board #Minimus Gainclone 70W”

  1. On this PCB layout we cant can’t make a circuit , those white line should be black and back should be white and many mistake are der in the board

  2. TONI are you sure 1µF – capacitor polyester will work for this , according to me lm3886 support Mkt 2.2uf or 1 uf Audio capacitor like Dayton . Polyester may not work . I tried it work working


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