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

The MAX97000 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 four inputs are configurable as two differential inputs or four single-ended inputs.

The entire subsystem is designed for maximum efficiency. The high-efficiency 725mW 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-levels signals without compromising the quality of large signals.

All control is performed using the 2-wire, I²C interface. The MAX97000 operate in the extended -40°C to +85°C temperature range, and is available in the 2mm x 2mm, 25-bump WLP package (0.4mm pitch).

Applications

* Cell Phones * Portable Multimedia Players

* 1.6V to 2.0V Headphone Supply Voltage

* 2.7V to 5.5V Speaker Supply Voltage

* Internal LDO Allows Single-Supply Operation

* 725mW Speaker Output (VPVDD = 3.7V, ZSPK = 8Ω + 68µH)

* 40mW/Channel Headphone Output (RHP = 16Ω)

* Low-Emission Class D Amplifier

* Efficient Class H Headphone Amplifier

* Ground-Referenced Headphone Outputs

* Two Stereo Single-Ended/Mono Differential Inputs

* Integrated Distortion Limiter (Speaker Outputs)

* Integrated DPST Analog Switch

* No Clicks and Pops

* TDMA Noise Free

* 2mm x 2mm, 25-Bump 0.4mm Pitch WLP Package