LM1875 Audio Amplifier

The LM1875 is a Class-AB Audio Amplifier from Texas Instruments. It can deliver an output power of 20W into a 4Ω or 8Ω speaker with a maximum current of 4A. The IC can operate in single rail or dual rail power supply and is commonly used in high power audio amplifier designs.

Pin Configuration 

Features

• Low frequency class AB amplifier most suited for audio amplification
• Operating Voltage: 16V to 60V
• Output: 20Watts with 4Ω/8 Ω speaker
• Output Current: 4A
• Open Loop Gain Gain: 90dB
• Bandwidth: 70KHz
• Short circuit and thermal protection is available
• Breadboard friendly
• Available in 5-pin TO220 package

Note: Complete Technical Details can be found at the LM1875 datasheet given at the end of this page.

Alternative to LM1875: TDA2050

Other Audio Amplifiers: LM386, TDA1554, TDA2030, TDA7294, TDA7265, TDA7279, TDA2005,

Introduction to LM1875

The LM1875 is a 20W Class AB audio amplifier with a wide operating voltage and high bandwidth. The IC can driver 20W speakers with a maximum current of 4A and can also go to a maximum of 30W.  It can operate in both with single rail and dual rail power supply, and has some in-built protection features making it robust.

The LM1875 is breadboard friendly and hence can be easily tested using a breadboard. A sample application circuit for LM1875 is given below. The datasheet given at the bottom of this page consists of more details on this design.

LM1875 is a 5-pin Amplifier IC. The pin 5 and 3 are used to power the Amplifier IC, and the audio signal to be amplified is given in through pin 1 which is the non-inverting input. The amplified audio output can be obtained through pin 4. The values of the components given above are the values recommended by manufactures.

Applications

• Used for Audio signal Amplification
• Suitable for high power amplification
• Capable of operating on dual/split power supply
• Can be used to cascade audio speakers

2-D Model (PDIP)