3W mono into 3Ω — the headline output
The LM4871MX/NOPB delivers 3W continuous into a 3Ω load from a single 5V rail — that is the full-scale output for a portable speaker or a single-cell Li-ion powered alert tone generator. Class AB topology keeps crossover distortion low at the expense of quiescent current — the tradeoff is acceptable for battery-powered voice or music playback under 1W average, where a Class D switching amp would add inductor noise and EMI filtering cost.
Shutdown pin (active-low) lets a GPIO from the host MCU cut the amplifier quiescent draw to near-zero when the speaker is idle — useful for extending standby time in a battery device.