ADAU1761 pops at power down

SigmaDSP & SigmaStudio ADIApproved Aug 6, 2014 00:00 1 replies Original on forum ↗

ADIApproved Question

Aug 6, 2014 00:00

Hi,

We are dealing with pops and could use some guidance.

We currently mute LHPM & RHPM before power-down but we do not change HPMODE bit as suggested in the datasheet. We do not change HPMODE bit because our application always uses headphones and should never need to switch to line output. However, does switching to HPMODE=0 reduce power-down pops by disabling the headphone circuitry?

Thanks,

Phil

Audio Signal Processors

SigmaDSP Audio Processors

adau1761

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JohnTo Reply

Aug 7, 2014 00:00

Hi Phil,

Just an FYI, there are some Linux drivers the customer can reference for the ADAU1761 and ADAU1361:

https://wiki.analog.com/resources/tools-software/linux-drivers/sound/adau1361#source_code

Can you have the customer try to first mute the DAC digital output section and mixer, then mute all of the outputs volume control registers for headphone, line-outs and mono output prior to entering powerdown mode? Something similar to the following pseudo-code:

#define ADAU_PLBMLC0 0x401C

#define ADAU_PLBMRC0 0x401E

#define ADAU_PLBHPVL 0x4023
#define ADAU_PLBHPVR 0x4024

#define ADAU_PLBLOVL 0x4025

#define ADAU_PLBLOVR 0x4026

#define ADAU_PLBMNOC 0x4027

#define ADAU_DACCTL0 0x402A

//Mute DAC output and mixer

adau1761_write_byte(ADAU_PLBMLC0, 0xFE);

adau1761_write_byte(ADAU_PLBMRC0 ,0xFE);

adau1761_write_byte(ADAU_DACCTL0 , 0xFD);

//Mute all output pins
adau1761_write_byte(ADAU_PLBHPVL, 0xE5);
adau1761_write_byte(ADAU_PLBHPVR, 0xE5);
adau1761_write_byte(ADAU_PLBLOVL, 0xE4);
adau1761_write_byte(ADAU_PLBLOVR, 0xE4);
adau1761_write_byte( ADAU_PLBMNOC, 0xE4);

//Powerdown Sequence

(...)

Regards,

-JT

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