Microphone AMP Board
The Microphone AMP Board is an accessory board that amplifies audio signals detected by the microphone provided on-board. The microphone is connected to a LM4864 audio power amplifier that works well for use in low-voltage consumer applications. The detected audio signals are amplified and sent to the connector used to connect a loudspeaker with an impedance of 4, 8, or 16 Ω. In order to keep the external part count low, the gain is internally set to 20. However, with the addition of a potentiometer and capacitor between pins 1 and 8, user can increase the gain up to 200. Microphone AMP Board is provided with screw terminals for easy connectivity. The power supply voltage has to be stabilized and in a range between 3.3V and 5V DC.
With such features, Microphone AMP Board is an ideal choice for general purpose audio applications, cellular phones, personal computers, and many more.
- LM4864 725mW Audio Power Amplifier
- Onboard screw terminals for easy connections
- 300 to 725mW output power (subject to power supply voltage and loudspeaker impedance)
- Loudspeaker impedance of 4, 8, or 16 ohm
- On-board microphone
- External gain configuration capability
- Thermal shutdown protection circuitry
- 3.3V to 5V power supply voltage
- Perfect for low-voltage applications
- Small footprint, compact design
- Affordable solution
IC/Module: LM4864 Audio Power Amplifier with Shutdown Mode
LM4864 is a 725mW audio power amplifier for a 5V power supply. Designed specifically to work on a low supply voltage with high quality output power, LM4864 requires a minimal amount of external components. This module does not require output coupling capacitors, bootstrap capacitors, or snubber circuits, making it fit for use in low-power portable applications.
Bridge Amplifier Design
The bridge amplifier design features some benefits over the single-ended configuration. It provides differential drive to the load, and thus doubles output swing for a specified supply voltage. It can provide four times the output power as compared to a single-ended amplifier. Another advantage is that it eliminates the need for an output coupling capacitor required in a single supply, single-ended amplifier configuration.
Microphone Amplifier User Manual
- Microphone AMP Board (1)