25 mW into 16 Ω from a 0.9 V rail
The MAX9721BEBC-T is a Class AB headphone amplifier from Analog Devices' DirectDrive® series, delivering 25 mW per channel into a 16 Ω load — enough drive for standard earbuds and in-ear monitors from a supply as low as 0.9 V. The mono output configuration with stereo headphone support means one channel drives both earpieces; the 0.9 V to 1.8 V supply range lets it run directly from a single-cell alkaline or Li-ion coin cell without a boost converter.
Supply headroom and battery-powered fit
Operating from 0.9 V to 1.8 V, this amplifier starts working when a battery has already dropped below 1.0 V, extending the usable runtime of a portable device. The -40°C to +85°C temperature grade covers consumer and industrial ambient ranges. The 12-UCSP package (2.02 x 1.54 mm) is a wafer-level chip-scale package — the footprint matches the die size, so the PCB land pattern must follow the application note exactly for solder-joint reliability under thermal cycling.