STW5095T datasheet(22/73 Pages) STMICROELECTRONICS

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STw5095

Functional description

21/72

4.16

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 10.4 on page 56.

Figure 4.

Plug-in and push-button detection application note

4.17

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 4.17 on page 21, and an application note is shown in

Section 18 on page 69.

Call/Answer Button

µF

1.5k

Ω

VCCA

Ω

200nF

AUX1L

AUX1R

CAPMIC

HDET

200nF

STw5095

Generic Connector

From Driver

STW5095T 데이터시트(PDF) 22 Page - STMicroelectronics