Package and integration story
The LM49350RL/NOPB is a fully integrated Class D audio sub-system in a 36-ball DSBGA (0.5 mm pitch) package — the board footprint is about 3.6 x 3.6 mm, so the audio chain fits into a space that would otherwise hold just the codec and a separate amplifier. The 36-WFBGA, DSBGA package demands a controlled-impedance layout for the I²S clock lines and a solid thermal via array under the centre pad to pull heat from the 2 W speaker channel. Supply voltage spans 2.7 V to 5.5 V — a single Li-ion cell (3.0-4.2 V) or a regulated 3.3 V / 5 V rail both work without an extra boost converter. The industrial temperature range of -40°C to 85°C covers outdoor kiosks, automotive cabin modules, and portable test gear that sees a hot dashboard.
Output power and channel configuration
The mono speaker channel delivers 2 W into 4 Ω — enough for a portable Bluetooth speaker or a panel-mount annunciator. The stereo headphone output provides 69 mW per channel into 32 Ω, which drives most consumer earbuds and studio headphones to comfortable listening levels without an external headphone amp. Output type is 1-channel (mono) with mono and stereo headphones — the part internally mixes the left/right digital audio stream to the mono speaker while keeping separate left/right paths for the headphone jack. This saves an external summing amplifier and a headphone switch.
Integrated features reduce BOM count
The LM49350RL/NOPB packs a DAC, I²C control interface, I²S digital audio input, depop circuitry, mute, volume control, and short-circuit/thermal protection — a typical audio subsystem that would need four or five discrete ICs (codec, DAC, headphone amp, speaker amp, volume controller) collapses into one 36-ball package. The I²C bus handles volume, mute, and mode switching; the I²S port accepts standard 16/24-bit audio data. Depop circuitry eliminates the audible pop when the amplifier powers up or switches modes — a common complaint in portable designs that this part handles internally. Short-circuit and thermal protection mean the output stage survives a momentary speaker-wire short without latching off permanently.
Lifecycle and sourcing reality
Sourced to order against the BOM quantity through authorized and independent distribution channels.