What this Boomer® stereo amp delivers
The Texas Instruments LM4920TL/NOPB is a Class AB stereo headphone amplifier from the Boomer® series, designed to drive 2-channel (stereo) headphones directly from a battery rail. It delivers 80 mW per channel into a 16 Ω load, which is enough output for most portable headphones and earbuds without requiring an external boost converter. The supply range of 1.6 V to 4.2 V maps directly to a single-cell lithium-ion battery — the amp keeps working from a full cell down to near the end-of-discharge voltage, which is a clean fit for handheld audio products, portable gaming, and wireless earbud charging cases. On-chip features include depop circuitry (eliminates the turn-on thump that can annoy users), a shutdown mode for battery conservation, and thermal protection that prevents the die from overheating if the output is shorted or driven hard into a low-impedance load.
The LM4920TL/NOPB comes in a 14-WFBGA / 14-DSBGA package — a fine-pitch wafer-level ball-grid array with 14 bumps. That footprint saves board space but demands a controlled reflow profile and a clean solder-paste stencil. Storage temperature exceeds this, but the part is rated for continuous operation across that full span.