The MAX9728A/MAX9728B stereo headphone amplifiers are designed for display and notebook applications or portable equipment where board space is at a premium. These devices use a unique DirectDrive architecture to produce a ground-referenced output from a single supply, eliminating the need for large DC-blocking capacitors, saving cost, board space, and component height. The MAX9728A offers an externally adjustable gain, while the MAX9728B has an internally preset gain of -1.5V/V. The MAX9728A/MAX9728B deliver up to 60mW per channel into a 32Ω load and have low 0.02% THD+N. An 80dB at 1kHz power-supply rejection ratio (PSRR) allows these devices to operate from noisy digital supplies without an additional linear regulator. Comprehensive click-and-pop circuitry suppresses audible clicks and pops on startup and shutdown. The MAX9728A/MAX9728B operate from a single 4.5V to 5.5V supply, consume only 3.5mA of supply current, feature short-circuit and thermal-overload protection, and are specified over the extended -40°C to +85°C temperature range. The devices are available in tiny 12-pin Thin QFN (3mm x 3mm x 0.8mm) and 14-pin TSSOP packages (5mm x 4.4mm x 1.1mm).
No Bulky DC-Blocking Capacitors Required
Low-Power Shutdown Mode, < 0.1µA
Adjustable Gain (MAX9728A) or Fixed -1.5V/V Gain (MAX9728B)