wm9081 Wolfson Microelectronics plc, wm9081 Datasheet - Page 49

• 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

Pre-Production
ANALOGUE OUTPUTS
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The WM9081 provides a mono Line Output and a mono Speaker Output. These are described
individually in the subsections below.
SPEAKER OUTPUT CONFIGURATION
The speaker output is a Class D BTL configuration by default. The speaker driver can be configured
to operate in Class AB mode by setting SPK_MODE = 1.
The analogue mixer circuit and the speaker PGA are powered by AVDD, whilst the speaker driver is
powered by SPKVDD. Six levels of AC and DC signal boost are provided in order to deliver
maximum output power for many commonly-used SPKVDD/AVDD combinations. These boost
options are available in both Class AB and Class D modes. The boost levels from 0dB to +5.1dB are
selected using register bits SPK_DCGAIN and SPK_ACGAIN. Note that the BTL output configuration
provides an additional 6dB gain. To prevent pop noise, these registers should not be modified while
the speaker outputs are enabled. Figure 33 illustrates the available mixing and speaker output
configuration. Table 28 shows the gain/boost options.
Ultra-low leakage and high PSRR allow the speaker supply SPKVDD to be directly connected to a
lithium battery. Note that an appropriate SPKVDD supply voltage must be provided to prevent
waveform clipping when speaker boost is used.
Figure 33 Speaker Gain Control
PP, Rev 3.0, April 2009
WM9081
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