wm9081 Wolfson Microelectronics plc, wm9081 Datasheet - Page 18

• Manufacturer Part Number: wm9081
• Description: Mono Dac With 2.6w Class Ab/d Speaker Driver, Dynamic Range Controller And Retune Mobile Parametric Equalizer
• Manufacturer: Wolfson Microelectronics plc

WM9081
DEVICE DESCRIPTION
INTRODUCTION
Figure 9 DAC Signal Path and Clocking Architecture
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The WM9081 is designed to provide high quality, high power output to a loudspeaker at low distortion
levels in space-constrained portable applications. The device is well-suited to both mono and multi-
channel speaker systems.
Digital input enables the power drivers to be located close to the speakers in multi-channel systems
without the need for troublesome long analogue connections. Location of the power drivers close to
the speakers also removes the need for bulky and expensive class D filters and reduces PCB track
lengths, minimising emissions.
The WM9081 supports both hardware and software control modes.
In Hardware control modes, the digital audio interface format is fixed and either the left or right
channel can be routed to the Class D speaker driver. The WM9081 is a slave device only on the
audio interface; EQ and Dynamic Range Control functions are not supported.
In Software control modes, the digital audio interface is highly programmable. Ready-programmed
control sequences can be commanded to enable/disable the speaker driver or line output.
Programmable EQ and Dynamic Range Control is supported in the digital domain. Analogue audio
input paths can also be mixed into the speaker or line output drivers. The speaker driver can be
configured to operate either in Class AB or in Class D mode.
ReTune Mobile parametric EQ with fully programmable coefficients is integrated for optimization of
speaker characteristics. A simple set-up mode is also available.
A programmable dynamic range controller is also available for maximizing loudness whilst also
protecting speakers from being overdriven, preventing battery droop, waveform clipping, thermal
overloads and premature system shutdown.
Figure 9 shows the DAC signal path and clocking architecture of the WM9081.
Digital audio transmission within the system also reduces crosstalk between, for example,
microphone input signals and speaker output signals, enhancing stability and reducing the risk of
‘howling’ during speakerphone operation where very high microphone gain is used.
Four control interface addresses and four stereo TDM slots are supported to allow multiple WM9081
devices to be configured and driven independently.
PP, Rev 3.0, April 2009
Pre-Production
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