Description

 

LM3886 Low Frequency Audio Power Amplifier Board OPA445 High Voltage Operational Amplifier Version

Attention:
(1) The module interfaces are clear and its performance is stable. Please use the schematic diagram provided by our shop to verify the function under the corresponding experimental conditions.
(2) The basic parameters of this module are mentioned below. Project files are not provided. You can consult customer service if you have operational problems.
(3) Before using the module, please read the details of this module in detail to understand the power supply and usage restrictions to avoid damage to the module due to improper operation.
(4) Provide the actual module parameters, functions and pictures of the module. All modules are shipped after testing.

Module Description:
LM3886 is a high-performance audio power amplifier, capable of delivering 68W of continuous average power to a 4Ω load at 0.1% THD at 20Hz-20kHz, and providing 38W of power to an 8Ω load. The performance of LM3886 utilizes its self-peak instantaneous temperature protection circuit to provide a safe working area with inherent dynamic protection, making it one grade higher than discrete and hybrid amplifiers. The output has been fully protected against overvoltage, undervoltage, overload, including power short circuit, thermal runaway and instantaneous temperature peaks.

LM3886 maintains an excellent SNR, greater than 92dB, with a typical low noise level of 2.0uV. In the audio frequency spectrum, under rated output under rated load, it has an extremely low THD+N of 0.03%, and has excellent linearity. It is suitable for motor drive speaker drive, transformer drive and audio amplifier. It can also amplify triangle wave, sine wave, and square wave signals.

Module Specifications:
- Model: LM3886
- Module type: low frequency power amplifier
- Input signal form: single-ended
- Input voltage range: 2Vpp (MAX) (usually within the power supply)
- Module input impedance: 10KΩ
- Module power supply voltage: ±4V to ±42V
- Module power supply current: ±7A (large output current requires large power supply current)
- Module output impedance: low impedance
- Output voltage range: 66Vpp (under ±40V power supply)
- Output current: 7A (MAX)
- Output power: 68W (MAX)
- Module gain: 44 times (default gain is 44 times, the first stage is 11 times, the second stage is 4 times, G1=R1/R2+1, G2=R11/R10+1)
- Input offset voltage: 1mV (MAX)
- Input offset drift: 2uV/℃ (MAX)
- Input bias current: 125nA (MAX)
- Input voltage noise: 35nV√Hz(1KHz)
- Module protection: None (no reverse connection protection, unlimited current protection)
- Module weight: 150g
- PCB size: 68*82*52mm
- Module heating: With heat sink (forced air cooling is required for high current)
- Module heating factor: input and output voltage are too large or the module is damaged
- Module working temperature: -40℃ to +75℃ (industrial grade)
- Module features: positive and negative power LED indication
- Applications: Small signal amplifier, audio signal amplifier, motor drive, servo amplifier, etc.
- Module interface type: SMA signal input and output, 5.08 blue power supply card socket

Package Included:
- 1 x Power Amplifier Board

 

Precautions:
(1) The power consumption of the module is large, and your power supply needs to have a certain margin. It is recommended to use a power supply with a current drive capability greater than 2 times the required output current. The module can only be powered by dual power supplies.
(2) In order to avoid unnecessary interference, it is recommended to use a linear power supply, and the power supply should not exceed ±42V.
(3) It is recommended to use a SMA to BNC cable to connect an oscilloscope to observe the effect of output signal. Poor contact or poor-quality wire may cause signal attenuation or excessive noise.
(4) SMA port cannot be used for power output, blue terminal block must be used. The SMA port is for observing signals and cannot be overpowered.
(5) Due to high power consumption and heat generation, pay attention to ventilation and heat dissipation during long-term work, and increase fan heat dissipation if necessary.
(6) Since the module has a fixed magnification and no external protection circuit, it is recommended to confirm the output power and amplitude before loading to avoid damage to the module.

FAQ:
Q: Is the magnification fixed? How to adjust?
A: The default magnification of the module is 44 times. If you need to adjust the magnification, you can only change the resistors on the board. The resistor package is 0805. The calculation formula has been given in the parameter details.

Q: Can the module directly drive coil?
A: The module can drive coil, but the internal resistance of the coil is required to be greater than 4Ω. If it is less than 4Ω, a power resistor must be connected in series, otherwise the module may be damaged.

Q: Can the module amplify square waves or pulses? What is the bandwidth of the module?
A: The module can amplify low-frequency square waves or pulses. Because it is an audio amplifier, the total bandwidth is not high, signals within 100K can be amplified, and the module is compatible with DC input.

Q: Can the module amplify 1:1? That is, only amplify current?
A: The module can support 1:1 amplification, and you need to modify the resistance configuration magnification by yourself. It is not recommended to directly configure to the op amp follower mode, which is easy to self-excite. It is recommended to change to resistance attenuation first, then operational amplification, the total gain is 1.

Q: Why is the input sine wave output as a square wave? What is the output current? What is the output power?
A: Generally speaking, if the input signal is too large, the operational amplifier will be amplified with cut-off distortion, which is a square wave, or the power supply voltage is not enough. This problem can be solved by reducing the input signal and increasing the supply voltage. The output current of the module is determined by the output voltage and load, I=Uout/R. Similarly, the output power P=U*I, which is determined by the output voltage and load resistance, can add heat dissipation silicone grease and wind when high-power input cold.

Q: Can I use the second stage without using the previous stage?
A: You can only use the second level, but you need to remove the first level chip, and then input the signal from OUT1. Otherwise, the first-level chip will affect the signal input.