3W mono Class D into a 3x3 mm footprint
The LM4670SD is a Texas Instruments Boomer® Class D audio amplifier delivering 3W continuous into a 4Ω load from a single 2.4V to 5.5V supply — enough output for a portable speaker or a notification chime driven off a Li-ion cell without a boost converter. The 8-WSON (3x3 mm) package with exposed pad sinks the heat from a 3W sine wave into the PCB copper plane; the thermal pad is the primary thermal path, not the plastic body.
Supply range and integrated protection
On-chip short-circuit protection and a shutdown pin let the system disable the output stage when the speaker is not needed, cutting quiescent draw to near-zero in a battery-powered design. Differential inputs reject common-mode noise picked up on the audio traces between the codec and the amplifier, which matters when the PCB layout routes analog audio past a switching regulator or a digital bus.
The 8-WSON (3x3 mm) supplier device package matches the 8-WFDFN with exposed pad — the footprint is a 3x3 mm DFN with a central thermal pad that must be soldered to a copper pour for the rated output power.
RoHS non-compliant per the manufacturer's listing — a factor for designs that must meet EU RoHS exemption limits; confirm the specific date-code compliance against your BOM's regulatory requirement.