Active part, still a solid choice for portable audio
The Texas Instruments LM4890MM/NOPB is a Class AB mono audio amplifier from the Boomer® series, rated for 1W into an 8Ω load. It runs on a 2.2V to 5.5V supply, so it fits single-cell Li-ion or 3.3V/5V rails without a regulator.
Package and mounting
1W into 8Ω at 5V supply is typical for a small speaker in a portable device — think audio alerts, voice prompts, or a headphone driver. The Class AB topology gives clean audio with low crossover distortion, but it's less efficient than Class D, so the thermal pad on the 8-VSSOP needs a decent copper pour if you're pushing continuous 1W. The Depop feature suppresses the pop on power-up, which saves a firmware workaround.
Supply and shutdown — practical points
Supply range from 2.2V to 5.5V means it runs happily from a Li-ion cell down to near-empty. The Shutdown pin lets you cut quiescent current to near zero for battery life — tie it to a GPIO and you're set. Thermal Protection kicks in if the die gets too hot, so a shorted output won't smoke the part immediately.
Lifecycle — no LTB worry
It's ROHS3 compliant, so it passes current environmental requirements without issue.