WM1811A datasheet(124/328 Pages) WOLFSON

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WM1811A

Production Data

PD, November 2013, Rev 4.1

124

ANALOGUE OUTPUTS

The speaker, headphone, earpiece and line outputs are highly configurable and may be used in many

different ways.

SPEAKER OUTPUT CONFIGURATIONS

The speaker outputs SPKOUTL and SPKOUTR can be driven by either of the speaker mixers,

SPKMIXL or SPKMIXR. Fine volume control is available on the speaker mixer paths using the

SPKLVOL and SPKRVOL PGAs. A boost function is available on the speaker output paths. For

information on the speaker mixing options, refer to the “Analogue Output Signal Path” section.

The speaker outputs SPKOUTL and SPKOUTR operate in a BTL configuration.

The speaker outputs can be configured as a pair of stereo outputs, or as a single mono output. Note

that, for applications requiring only a single speaker output, it is possible to improve the THD

performance by configuring the speaker outputs in mono mode.See “Typical Performance” for further

details.

The mono configuration is selected by applying a logic high input to the SPKMODE pin (D5), as

described in Table 71. For Stereo mode this pin should be connected to GND. Note that SPKMODE is

referenced to DBVDD1.

An internal pull-up resistor is enabled by default on the SPKMODE pin; this can be configured using

the SPKMODE_PU register bit described in Table 72.

SPEAKER CONFIGURATION

SPKMODE PIN (D5)

Stereo Mode

GND

Mono Mode

DBVDD1

Table 71 SPKMODE Pin Function

In the mono configuration, the P channels, SPKOUTLP and SPKOUTRP should be connected

together on the PCB, and similarly with the N channels, SPKOUTLN and SPKOUTRN, as illustrated in

Figure 30. In this configuration bothleft and right speaker drivers should be enabled

(SPKOUTL_ENA=1 and SPKOUTR_ENA=1), but path selection and volume controls are available on

left channel only (SPKMIXL, SPKLVOL and SPKOUTLBOOST).

Note that the minimum speaker load resistance and the maximum power output has a dependency on

the SPKMODE output configuration, and also on the Class D/AB mode selection. See “Electrical

Characteristics” for further details.

Stereo

Mono

Figure 30 Stereo / Mono Speaker Output Configurations

WM1811A Datasheet(PDF) 124 Page - Wolfson Microelectronics plc