The MAX9723 is a stereo DirectDrive® headphone amplifier with BassMax and volume control from MAXIM. It is ideal for portable audio applications where space is at a premium and performance is essential. The device operates from a single 1.8V to 3.6V power supply and includes features that reduce external component count, system cost, board space, and improve audio reproduction. The headphone amplifier uses Maxim's patented DirectDrive architecture that produces a ground-referenced output from a single supply, eliminating the need for large DC-blocking capacitors. The headphone amplifiers deliver 62mW into a 16Ω load, feature low 0.006% THD+N, and high 90dB PSRR. The MAX9723 features Maxim's industry-leading click-and-pop suppression. The BassMax feature boosts the bass response of the amplifier, improving audio reproduction when using inexpensive headphones. The integrated volume control features 32 discrete volume levels, eliminating the need for an external potentiometer. BassMax and the volume control are enabled through the I2C/SMBus™-compatible interface. Shutdown is controlled through either the hardware or software interfaces. The MAX9723 consumes only 3.7mA of supply current at 1.8V, provides short-circuit and thermal-overload protection, and is fully specified over the extended -40°C to +85°C temperature range. The MAX9723 is available in a tiny (2mm x 2mm x 0.62mm) 16-bump chip-scale package (UCSP™) or 16-pin thin QFN (4mm x 4mm x 0.8mm) package. Applications
The MAX9723 is a stereo DirectDrive® headphone amplifier designed for portable audio applications where space and performance are critical. It operates from a single 1.8 V to 3.6 V supply, provides 62 mW into a 16 Ω load, and includes features such as BassMax bass boost, integrated 32‑level digital volume control, and industry‑leading click‑and‑pop suppression. The I²C/SMBus‑compatible interface enables software control of volume, BassMax, and shutdown.
The datasheet specifies electrical characteristics, timing parameters, distortion and crosstalk performance, and package options (16‑bump UCSP or 16‑pin thin QFN). It also describes the charge‑pump architecture that creates a negative supply internally, eliminating the need for large DC‑blocking capacitors and improving low‑frequency response.
| Supply Voltage Range | 1.8 V to 3.6 V |
|---|---|
| Output Power (16 Ω load) | 62 mW |
| Total Harmonic Distortion + Noise | 0.006 % |
| Power‑Supply Rejection Ratio | 90 dB |
| Volume Control Levels | 32 discrete levels |
| Shutdown Supply Current | 5 µA |
The MAX9723 operates from a single 1.8 V to 3.6 V power supply.
It can deliver 62 mW into a 16 Ω load.
The amplifier includes an integrated 32‑level digital volume control.
In shutdown mode the device consumes only 5 µA.