1W mono output into 8Ω — what it means for the speaker load
The LM4890M/NOPB delivers 1W continuous into an 8Ω load from a single 5V supply — enough drive for a small loudspeaker or piezoelectric transducer in a portable device. The 1W figure is the max output power at 10% THD+N; for cleaner audio, the usable output sits lower, typically around 0.5W at 1% THD+N, which still covers most alert-tone and voice-reproduction applications. Supply range spans 2.2V to 5.5V, so the amplifier runs directly from a Li-ion cell (3.0-4.2V) or a regulated 3.3V/5V rail without an extra boost converter. The lower end at 2.2V means it keeps producing audio as the battery discharges near its cutoff.
SOIC-8 footprint and board integration
The exposed paddle on the bottom (if present on the die-attach version) is not connected electrically but can be soldered to a PCB copper pour for improved thermal dissipation — though at 1W output, the junction temperature stays well within limits even without a dedicated heatsink. No special reflow profile beyond standard lead-free (260°C peak) is required.
Active lifecycle and compliance documentation
The part is ROHS3 Compliant (the /NOPB suffix indicates lead-free and RoHS), so it fits current EU and global regulatory requirements without exemption paperwork. For designs requiring extended temperature or AEC-Q100 qualification, a different part from the Boomer family would be needed — this grade is commercial/industrial.
Built-in pop suppression and thermal protection
The Depop feature ramps the output bias voltage slowly at power-up and power-down, reducing the audible click that otherwise couples into the speaker when the amplifier turns on. This matters in battery-powered devices where the supply rail ramps gradually and the microcontroller may toggle the shutdown pin. Thermal Protection shuts down the output stage if the die temperature exceeds approximately 150°C, protecting the amplifier and the speaker load from sustained overdrive. The shutdown pin also lets a host processor place the amplifier in a low-current state (typically <1 µA) when audio is not needed.