The WM8991 is a low power Hi-Fi stereo CODEC designed for mobile handsets and other portable devices rich in multimedia features such as mobile TV, wireless VoIP, Bluetooth®, GPS, gaming, FM radio and digital audio playback. Offering an exceptional level of integration, the WM8991 provides interfaces to many peripheral modules in addition to the core Hi-Fi functions. Ultra-low leakage and high PSRR allow the powerful 1W speaker driver to be powered directly from a lithium battery, saving space and reducing component count. Its high efficiency and fully internal signal boosting allow output volume to be maximised whilst minimising internal power consumption. Four headphone outputs support fully differential headset drive, enhancing signal quality and eliminating large and expensive DC-blocking capacitors. Powerful GPIO features are available for interfacing buttons, accessories or other digital circuitry. Highly flexible internal signal routing and mixing options support a wide variety of system arch