70 mW per channel into 8 ohm — what that means for a headphone output stage
The TPA122DGNRG4 is a Class AB stereo amplifier delivering 70 mW per channel into an 8 ohm load — enough drive for low-impedance earbuds or small on-ear headphones in portable gear. The 2.5 V to 5.5 V supply range lets it run from a single Li-ion cell or a 3.3 V rail without a separate audio regulator. Built-in depop circuitry suppresses the turn-on thump that otherwise couples into the headphones. Short-circuit and thermal protection keep the output stage from failing if the headphone jack is plugged or unplugged while powered.
Package and layout — the PowerPad matters
Housed in the 8-MSOP-PowerPad, the exposed pad on the underside must be soldered to a thermal land on the PCB — without it the junction temperature rises quickly under continuous output. The pad also serves as the ground return; a single via under the pad to the ground plane keeps the thermal and electrical path short. Surface-mount only — no through-hole variant. The 8-pin MSOP footprint is common, but the PowerPad adds a centre land that a standard MSOP-8 layout does not have; verify the PCB footprint matches the exposed-pad dimension.
Active and ROHS3 compliant — no last-time-buy pressure
It remains a valid BOM line for new designs and replacement builds.