STW5095 datasheet(19/69 Pages) STMICROELECTRONICS

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STw5095

3 Functional Description

19/69

3.16

Headset plug-in and push-button detection

STw5095 can detect the plug-in of a microphone connector and the press/release event of a

call/answer push-button. An application example can be found below, while specifications can

be found in

Section 9.4 on page 54.

3.17

Microphone biasing circuit

The Microphone Biasing Circuit can drive mono or stereo microphones and can switch them off

when not needed in order to save the current used by the microphone biasing network. Two bits

control the behavior of the microphone bias circuit: MBIAS in CR17 enables the circuit (fixed

voltage at MBIAS pin), while bit MBIASPD in CR17 affects the behavior of MBIAS pin when the

function is not enabled. In particular when MBIASPD=1 the MBIAS pin is pulled down,

otherwise it is left in tristate mode. The specification for the microphone biasing circuit can be

found in

Section 9.6 on page 55, and an application note is shown in Section 17 on page 66.

Figure 3.

Plug-in and push-button detection application note

Call/Answer Button

µF

1.5k

Ω

VCCA

Ω

200nF

AUX1L

AUX1R

CAPMIC

HDET

200nF

STw5095

Generic Connector

From Driver

STW5095 Datasheet(PDF) 19 Page - STMicroelectronics