1.1 W mono into 8 Ω — the output power ceiling
Rated 1.1 W continuous into an 8 Ω load from a single channel — this is the maximum output power before clipping at the specified supply and THD level. For a portable speaker or headphone driver, that figure sets the loudspeaker sensitivity requirement: a 1 W amplifier driving an 85 dB/W/m speaker yields 85 dB SPL at one meter, enough for personal listening but not room-filling volume. The mono output means the TPA4861DR drives one speaker or earpiece. For stereo applications, two devices are needed — one per channel, sharing the same supply rail.
The wide range means the amplifier continues to function as the battery discharges down to 2.7 V, though output power derates with supply voltage. A portable device left in a car dashboard on a summer day or used in an outdoor kiosk stays within the operating envelope.
Protection features and shutdown
Includes short-circuit protection on the output and thermal shutdown that disables the amplifier if the die temperature exceeds the safe limit. The shutdown pin lets a microcontroller or GPIO hold the amplifier in low-power idle between audio bursts, saving battery current.