LM1875 low frequency power amplifier module high voltage high current power amplifier board motor drive 55V peak -79411
product detail
Parameter:
Module model: LM1875
Module type: low frequency power amplifier
Input signal form: single-ended
Input voltage range: 2Vpp (MAX); generally within the power supply
Module input impedance: 10K ohm
Module supply voltage: ± 8V ～ ± 30V
Module power supply current: ± 4A output current is large, the power supply current is large
Module output impedance: low impedance
Output voltage range: 55Vpp (MAX); in the case of positive and negative 30V power supply
Output current: 4A (MAX)
Output power: 30W (MAX)
Module gain: 44 times; the default gain is 44 times, the first level is 11 times, the second level is 4 times, G1 = R2 / R1 + 1, G2 = R8 / R10 + 1
Input offset voltage: 3mV (MAX)
Input offset drift: 10uV / ℃ (MAX)
Input bias current: 125nA (MAX)
Input voltage noise: 35nV√Hz (1KHz)
Module protection: none; no reverse connection protection, unlimited current protection
Module heating: with heat sink; forced air cooling is required at high current
Module heating factors: the input and output voltage is too large or the module is damaged
Module working temperature: -40 ℃-+ 75 ℃; industrial grade
Module features: positive and negative power LED indication
Applications: small signal amplification, audio signal amplifier, motor drive, servo amplifier, etc.
Module interface type: SMA signal signal input and output, 5.08 blue power card wire holder.
Description:
Lm1875 is a single-chip power amplifier product with very low distortion and high quality performance for consumer audio applications. The lm1875 provides 20 watts of power to a 4 - or 8-ohm load on a ± 25V power supply. With 8 ohm load and ± 30V power supply, it can provide more than 30W power. The amplifier is designed to work with a minimum of external components. Equipment overload protection includes internal current limitation and thermal shutdown.
The lm1875 design utilizes advanced circuit technology and processing power to achieve extremely low distortion even at high output power level. Other outstanding features include high gain, fast swing rate and wide power bandwidth, large output voltage swing, large current capacity and very wide power supply range. It is suitable for motor driven horn drive, transformer drive and audio amplifier. It can also amplify triangle wave, sine wave and square wave signals.
(1) The power consumption of the module is large, and the power supply needs to have a certain margin. It is recommended to use a power supply with a current drive capacity greater than twice the 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, the power supply cannot exceed 30V.
(3) It is recommended to use the SMA to BNC cable to directly observe the output signal for the output signal. Poor contact or poor quality wires may cause signal attenuation or excessive noise.
(4) The SMA port is not available for power output, and a blue terminal block must be used. The SMA port is for observing the signal and must not overpower.
(5) Due to the large power consumption and heat generation, pay attention to ventilation and heat dissipation for long-term work, and add fans to strengthen 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.
Frequently asked questions
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 replace the resistor on the board. The resistance package is 0805. The calculation formula is given in the parameter details.
Q: Can the module directly drive the coil?
A: The module can drive the coil, but the internal resistance of the coil is required to be greater than 4 ohms. If it is less than 4 ohms, a series power resistance is required, otherwise the module may be damaged.
Q: Can the module amplify square wave or pulse? What is the module bandwidth?
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. The module is compatible with DC input.
Q: Can the module be enlarged 1: 1? That is to only amplify the current?
A: The module can support 1: 1 amplification, you need to modify the resistance configuration magnification yourself. It is not recommended to directly configure the op amp follow mode, which is easy to self-excitation. It is recommended to change to resistance attenuation first, and then operation amplification The total gain is only 1.
Q: Why the input sine wave output is square wave? What is the output current? What is the output power?
A: Generally speaking, the input signal is too large, and the op amp is amplified to the cut-off distortion, which is the square wave, or the supply voltage is not enough. Can reduce the input signal and increase the supply voltage to solve. The output current of the module is determined by the output voltage and the load. I = Uout / R. Similarly, the output power P = U * I is also determined by the output voltage and the load resistance. When high power is input, heat dissipation grease and air cooling can be added.
Q: Can I use the second level directly instead of the first level?
A: You can use the second stage directly, but you need to remove the chip of the first stage, and then input the signal from OUT1. Otherwise, the first-level chip will affect the signal input.
