Audio Subsystem with Mono Class D Speaker and Class H Headphone Amplifiers

The MAX97001 mono audio subsystem combines a mono speaker amplifier with a stereo headphone amplifier and an analog DPST switch. The headphone and speaker amplifiers have independent volume control and on/off control. The 4 inputs are configurable as 2 differential inputs or 4 single-ended inputs.

The entire subsystem is designed for maximum efficiency. The high-efficiency, 700mW, Class D speaker amplifier operates directly from the battery and consumes no more than 1µA in shutdown mode. The Class H headphone amplifier utilizes a dual-mode charge pump to maximize efficiency while outputting a ground-referenced signal that does not require output coupling capacitors.

The speaker amplifier incorporates a distortion limiter to automatically reduce the volume level when excessive clipping occurs. This allows high gain for low-level signals without compromising the quality of large signals.

All control is performed using the 2-wire I²C interface. The MAX97001 operates over the extended -40°C to +85°C temperature range, and is available in the 2mm x 2.5mm, 20-bump, WLP package (0.5mm pitch).

Applications

* Cell Phones * Portable Multimedia Players

* 2.7V to 5.5V Speaker Supply Voltage

* 1.6V to 2V Headphone Supply Voltage

* 700mW Speaker Output (VPVDD = 3.7V, ZSPK = 8Ω + 68µH)

* 37mW/Channel Headphone Output (RHP = 16Ω)

* Low-Emission Class D Amplifier

* Efficient Class H Headphone Amplifier

* Ground-Referenced Headphone Outputs

* 2 Stereo Single-Ended/Mono Differential Inputs

* Integrated Distortion Limiter (Speaker Outputs)

* Integrated DPST Analog Switch

* No Clicks and Pops

* TDMA Noise Free

* 2mm x 2.5mm, 20-Bump, 0.5mm Pitch WLP Package