I'm trying to design a circuit in which a microcontroller produces a signal and then using an amplifier drives an 8ohm speaker.
I've so far used LM386, but it cannot go above 1W, which turned out to be insufficient.
Besides that, I wish to add an (second order) anti aliasing LPF at the output of the microcontroller.
The general schematic is below.
If I wish to feed the speaker with 2W, then I would need 4v, 500mA on the speaker.
Is it possible for me to do it this way, or is there a better circuit for my needs?
Is there an op amp that can comply with these requirements?
Best Answer
There are several power op amps, and also audio amplifier ICs, which would meet the stated requirements. However, this approach may be overkill for the kind of fidelity likely from the signal generation source.
As mentioned in a comment to the question, adding a transistor buffer stage is perhaps the best way to achieve the desired results.
Also, do note that a dual-rail (+/- x Volts) supply at a relatively high voltage is needed for these op-amps / chip-amps. While the dual-rail requirement can be circumvented with a suitable virtual ground implementation, voltages involved are still not your run-of-the-mill logic voltage range.
In any case, to answer the question...
Some suitable Op Amps:
Some suitable Audio Amps: