Q: What is the correct sequence to reduce pop noise on headset output?
A: Follow the sequence below:
For powering on the headset amplifiers for use in application mode follow the sequence below:
§ Turn ON external mute control line by writing a ‘1’ to EXTMUTE (HS_POPN_SET[5])
§ Enable VMID buffer control by writing a ‘1’ to VMID_EN(HS_POPN_SET[6])
§ Power ON the headset amplifier by configuring the register HS_GAIN_SET. Select appropriate gain level.
§ Set RAMP_EN(HS_POPN_SET[1]) to ‘1’ and select appropriate delay using the field RAMP_DELAY.
§ Wait at least 10msec before the next step
§ Turn OFF external mute control line by writing ‘0’ to EXTMUTE.
For powering down the headset amplifiers after using in application mode follow the sequence below:
§ Turn ON external mute control line by writing a ‘1’ to EXTMUTE
§ Set RAMP_EN to ‘0’
§ Wait at least 10msec before the next step
§ Power down the headset amplifier by configuring the register HS_GAIN_SET
§ Disable VMID buffer control by writing ‘0’ to VMID_EN
§ Turn OFF external mute control line by writing ‘0’ to EXTMUTE
If the 10ms delay is not provided then pop noise will be heard. If external FETs are not used then ignore the corresponding step.
