Wolfson offers a broad portfolio of audio product solutions for portable navigation systems. These products have a range of features suitable for everything from entry level navigation systems requiring voice driven direction commands to top of the range navigation devices which incorporate functions such as Bluetooth communications, multimedia playback, mobile television, and FM radio modes.

Entry level navigation systems rely on a digital audio interface between the system processor and the audio IC. This device is typically a high performance, low power DAC which converts the digital audio signal into the analogue domain, then amplifies the voice command to a clear and intelligible level for the system user to hear the loudspeaker in a noisy automotive environment. The loudspeaker is typically driven by a class D amplifier powered from the 5V supply, delivering over 2W of output power from a 4 Ohm load. WM9081 is a single chip solution capable of meeting all of these features in a small 4x4 mm QFN COL package. WM9081 is a 24 bit mono DAC with I²S interface and an integrated class D speaker driver capable of delivering 2.4W into a 4Ohm speaker load at 1% THD+N. Enhanced digital signal processing functions such as a fully programmable 5 band parametric equaliser allow users to compensate the frequency response of the speaker or customise music profiles. A dynamic range compressor (DRC) and limiter prevent the audio signal from clipping and causing audible distortion, overloading the battery and potentially damaging the speakers whilst the DRC automatically boosts low level signals to maximize volume for improved intelligibility.

• PND Entry level
• PND Mid tier
• PND High end

WM9081
Mono DAC with integrated 2.5W class D speaker amplifier

WM8711
Stereo DAC with Headphone amplifier and line outputs

WM9001
1.2W class D mono speaker driver

WM8976
Low power stereo codec, mono ADC

WM8311
Integrated Power Management Subsystem

APPLICATION NOTES

WAN0204
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WHITE PAPERS

Getting the most out of your battery
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Class D audio design tips
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Class D Amplifiers empower mobile multimedia
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Class D Basics
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LINUX SOFTWARE

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