WM1811A datasheet(133/328 Pages) WOLFSON

133 / 328 page

Production Data

WM1811A

PD, November 2013, Rev 4.1

133

To configure the WM1811A in its lowest power condition, also supporting the Jack Detect function, the

following actions are recommended:



Select lowest power Jack Detection mode (JACKDET_MODE = 10)



Select 32kHz SYSCLK



Disable the Thermal sensor (TSHUT_ENA = 0)



Configure LDO1 output to float when disabled (LDO1_DISCH = 0)



Minimise any static current leakage paths on digital inputs where internal pull-up or pull-

down resistors are enabled (ie. disable the pull-up/pull-down resistors on these inputs)

Care should be taken to restore all applicable device settings when normal operation is resumed

following the low power jack detection. In particular, note that the thermal sensor should be enabled

for normal operation.

A recommended connection circuit, including headphone output on HPOUT1 and microphone

connections, is shown in Figure 39. See “Applications Information” for details of recommended

external components.

Figure 39 Jack Detect and External Accessory Connections

The internal comparator circuit used to detect the JACKDET status is illustrated in Figure 40.

The threshold voltages for the jack detect circuit are noted in the “Electrical Characteristics”. Note that

separate thresholds are defined for jack insertion and jack removal.

JACKDET

reference

AVDD2

Jack Detect logic

(jack insertion switch)

Note: The illustrated circuit assumes the

jack insertion switch contacts are closed

when jack is inserted.

WM1811A

Figure 40 Jack Detect Comparator

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