LM4935RLEVAL datasheet(37/91 Pages) TI1

37 / 91 page

Stereo +

Cellular

Stereo

Stereo +

Cellular

LM4935, LM4935RLEVAL

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SNAS296D – OCTOBER 2005 – REVISED MARCH 2006

Note that since the first effect of a series button press (microphone disconnected) is indistinguishable from

headset removal, the debounce time for series button press in defined by HS_DBNC_TIME.

Headset and push button detection can be enabled by setting CHIP_MODE 0; bit 0 of BASIC (0x00h). For

reliable headset / push button detection all following bits should be defined before enabling the headset

detection system:

1) the OCL-bit (AC-Coupled / Capless headphone interface (bit 7 of BASIC (0x00h))

2) the headset insert/removal debounce settings (bit 6:3 of DETECT (0x17h))

3) the BTN_TYPE-bit (Parallel / Series push button type (bit 3 of MIC_2 (0x0Ch))

4) the parallel push button debounce settings (bit 5:4 of MIC_2 (0x0Ch))

Figure 4-12 shows terminal connections and jack configuration for various headsets. Care should be taken

to avoid any DC path from the MIC_DET pin to ground when a headset is not inserted.

Figure 4-12. Headset Configurations Supported by the LM4935

The wiring of the headset jack to the LM4935 will depend on the intended mode of the headphone

amplifier:

Application Information

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LM4935RLEVAL Datasheet(PDF) 37 Page - Texas Instruments