CS47L35 datasheet(236/300 Pages) CIRRUS

236 / 300 page

236

DS1085F3

CS47L35

5.1 Recommended External Components

Figure 5-11. External Accessory Detection

The accessory detection circuit measures the impedance of an external load connected to one of the MICDET pins.

The microphone-detection circuit uses MICVDD, MICBIAS1A, MICBIAS1B, or MICBIAS2A as a reference. The applicable

source is configured using MICD_BIAS_SRC.

The CS47L35 can detect the presence of a typical microphone and up to six push buttons, using the components shown

in Fig. 5-12. When the microphone detection circuit is enabled, each of the push buttons shown causes a different bit in

the MICD_LVL field to be set.

The choice of external resistor values must take into account the impedance of the microphone—the detected impedance

corresponds to the combined parallel resistance of the microphone and any asserted push button. The components shown

in Fig. 5-12 are examples only, assuming default impedance measurement ranges and a microphone impedance of 1 k



or higher.

HPOUTL

HPOUTR

HPOUTFB1

JACKDETn

MICDET1

Note: The illustrated circuit

assumes the jack insertion

switch contacts are closed

when the jack is inserted.

* Note that the IN1Bxx analog mic

channels are recommended with the

external accessory detect function

(jack insertion switch )

MICBIASnx

2.2 k

(±2%)

* IN1BLP, IN1BRP

CS47L35

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