NS LM3886 is a mono audio power amplifier chip, using an 11-foot TO-220 package, the back of the "TF" suffix is ??????fully insulated package meant. And compared to LM1875T, LM3886 is more powerful, at the rated working voltage up to 68W continuous average power without distortion, also has a relatively perfect over-voltage over-current overheating protection function, in addition it has a function of current anti switch automatically when shock, the speaker may be possible to avoid current surge when the amplifier power is turned on causing injury.
LM3886 performance parameters:
VCC = ± 28V OUTPUT = 68W / 4Ω, 38W / 8Ω
VCC = ± 35V OUTPUT = 50W / 8Ω
Peak power: 135W
Conversion rate: 19V / us
Intermodulation distortion: 0.04%
The amplifier board has the following characteristics:
1. Using double-sided alignment, careful layout, signal input portion away from the output section.
2. Part of the coupling capacitors for longer minimum pad 5mm, the maximum suitable for the capacitor of 10mm.
3. The input section added high pass circuit, making the board more stable!
4. The output part RL circuit (inductance and resistance in parallel) effective protection chip, effectively preventing the induced electromotive force shutdown speaker damage to the chip!
1. Sheet glass fiber 1.6, size: 106 * 54mm, chip pitch of 51mm. Widening output section traces, and left large electrical flow tin!
2. LM3886 (original disassemble) is insulated version without the installation of the insulation sheet! Use some grease on the line.
1. The amplifier plate cannot connect directly to the transformer output end of the power plate, and then from the power board to the power supply panel, pay attention to the positive negative electrode level.
2. The plate uses DC power supply, speaker output impedance smaller current increases, the greater the heat, it is recommended when the speaker is 4Ω, the voltage suggested the use of ± 28V (transformer dual 21V). The speaker of 8Ω, voltage suggested ± 32V (transformer dual 24V), the highest possible ± 35V (transformer dual 28V), but pay attention to the local grid voltage is stable, it is recommended not to use.
3. When doing power test, the signal input on the board to the load, can not be suspended, otherwise it will may induction noise, the signal line to make use of shielded cable.
4. Be sure that the board chassis of the housing is connected to the input ground, if added to the front stage, the input stage is not necessary to draw a box, as long as the preceding stage input connected to chassis ground, then both will cause ground loops, noise.
1 x HiFi LM3886 TF Stereo Amplifier AMP Assembled Board