The Texas Instruments LM4871LD/NOPB is a Boomer® series Class AB audio power amplifier delivering 3W into a 3Ω load from a single mono channel. It operates from a 2V to 5.5V supply, covering single-cell Li-ion and 3.3V or 5V regulated rails. The 8-WSON (4x4) package with exposed pad suits space-constrained portable designs — speakers, headsets, toys, and battery-powered audio peripherals. Shutdown and thermal protection are integrated, so the part can idle with minimal draw and survive a stalled speaker coil without latching up.
Supply range and output power — the fit decision
The 2V to 5.5V supply range means this amplifier runs directly from a Li-ion cell (3.0V to 4.2V) without a boost converter, saving board space and BOM cost. The 3W into 3Ω rating is the headline number — but that's at 5V with a 3Ω load. At 3.6V into an 8Ω speaker, expect roughly 1W. If your design uses a 4Ω or 8Ω speaker, the output power will be lower; check the load line in the datasheet. The shutdown pin lets a GPIO or PMIC cut supply current to near-zero when audio is off, which matters for battery life in intermittent-use products.
Package and thermal — WSON exposed pad layout
It is ROHS3 compliant.