MAX9867 datasheet(43/55 Pages) MAXIM

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Ultra-Low Power Stereo Audio Codec

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Mode Configuration

The MAX9867 includes circuitry to minimize click-and-

pop during volume changes, detect headsets, and con-

figure the headphone amplifier mode. Both volume

slewing and zero-crossing detection are included to

ensure click-and-pop free volume transitions. Table 16

is the mode configuration register.

Headset Detection Overview

The MAX9867 features headset detection that can detect

the insertion and removal of a jack as well as the load

type. When a jack is detected, an interrupt on IRQ can be

triggered to alert the microcontroller of the event. Figure 7

shows the typical configuration for jack detection.

Sleep-Mode Headset Detection

When the MAX9867 is in shutdown and the power supply

is available, sleep-mode headset detection can be

enabled to detect jack insertion. Sleep mode applies a

4µA pullup current to JACKSNS/AUX and LOUTP that

forces the voltage on JACKSNS/AUX and LOUTP to

AVDD when no load is applied. When a jack is inserted,

either JACKSNS, LOUTP (assuming the headphone

amplifier is not configured in single-ended mode), or both

are loaded sufficiently to reduce the output voltage to

nearly 0V and clear the JKSNS or LSNS bits, respectively.

The change in the LSNS and JKSNS bits sets JDET and

triggers an interrupt on IRQ if IJDET is set. The interrupt

signals the microcontroller that a jack has been inserted,

allowing the microcontroller to respond as desired.

Powered-On Headset Detection

When the MAX9867 is in normal operation and the micro-

phone interface is enabled, jack insertion and removal can

be detected through the JACKSNS/AUX pin. As shown in

Figure 7, VMIC is pulled up by MICBIAS. When a micro-

phone is connected, VMIC is assumed to be between 0V

and 95% of VMICBIAS. If the jack is removed, VMIC increas-

es to VMICBIAS. This event causes JKMIC to be set, alert-

ing the system that the headset has been removed.

Alternatively, if the jack is inserted, VMIC decreases to

below 95% of VMICBIAS and JKMIC is cleared, alerting the

system that a jack has been inserted. The JKMIC bit can

be configured to create a hardware interrupt that alerts the

microcontroller of jack removal and insertion events.

Headphone Modes

The headphone amplifier supports differential, single-

ended, and capacitorless output modes, as shown in

Figure 8. In each mode, the amplifier can be configured

for stereo or mono operation. The differential and

capacitorless modes are inherently click and pop free.

The single-ended mode optionally includes click-and-

pop reduction to eliminate the click and pop that would

normally be caused by the output coupling capacitor.

When click-and-pop reduction is not required in the sin-

gle-ended configuration, leave LOUTN and ROUTN

unconnected.

GND

MIC

HPR

HPL

LOUTP

ROUTP

MICBIAS

JACKSNS/AUX

MICLP

LOUTN

Figure 7. Typical Configuration for Headset Detection

LOUTP

LOUTN

ROUTP

ROUTN

DIFFERENTIAL

LOUTP

LOUTN

ROUTP

ROUTN

CAPACITORLESS

µF

LOUTP

220

µF

LOUTN

SINGLE ENDED

µF

ROUTP

220

µF

ROUTN

OPTIONAL COMPONENTS REQUIRED FOR CLICK AND POP SUPPRESSION ONLY

Figure 8. Headphone Amplifier Modes

MAX9867 Datasheet(PDF) 43 Page - Maxim Integrated Products

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