SGTL5000XNAA3 Datasheet, PDF (32/84 Pages) Freescale Semiconductor, Inc – Low Power Stereo Codec with Headphone Amp

SGTL5000
DATASHEET
The ADC has an available Zero-Cross Detect (ZCD) that will prevent any volume
change until a zero-volt crossing of the audio signal is detected. This helps in elimi-
nating pop or other audio anomalies. If the ADC is to be used, the chip reference
bias current should not be set to -50% when in 3V mode.
5.7.
Analog Outputs
The SGTL5000 contains a single stereo DAC that can be used to drive a heapdhone
output and a line output. The DAC receives its input from the audio switch. The
headphone output and the line output can be driven at the same time from the DAC.
The headphone output can also be driven directly by the line input bypassing the
ADC and DAC for a very low power mode of operation.
The headphone output is powered by VDDA while the line output is powered by
VDDIO. This allows the headphone output to be run at the lowest possible voltage
while the line output can still meet line output level requirements.
5.7.1.
DAC
The DAC output is routed to the headphone and the dedicated line output.
The DAC output has a digital volume control from -90dB to 0dB in ~.5dB step sizes.
This volume is shared among headphone output and line output. The register
CHIP_DAC_VOL controls the DAC volume.
5.7.2.
Headphone
Stereo headphone outputs are provided which can be used to drive a headphone
load or a line level output. The headphone output has its own independent analog
volume control with a volume range of -52dB to +12dB in .5dB step sizes. This vol-
ume control can be used in addition to the DAC volume control. For best perfor-
mance the DAC volume control should be left at 0dB until the headphone is brought
to its lowest setting of -52dB. The register CHIP_ANA_HP_CTRL is used to control
the headphone volume.
The headphone output has an independent mute that is controlled by the register
field CHIP_ANA_CTRL->MUTE_HP.
The line input is routed to the headphone output by writing CHIP_ANA_CTRL-
>SELECT_HP. This selection bypasses the ADC and audio switch and routes the
line input directly to the headphone output to enable a very low power pass through.
When the line input is routed to the headphone output, only the headphone analog
volume and mute will affect the headphone output.
The headphone has an available zero cross detect (ZCD) which, as previously
described, will prevent any volume change until a zero-volt crossing of the audio
signal is detected. This helps in eliminating pop or other audio anomalies.
5.7.3.
Line Outputs
The SGTL5000 contains a stereo line output. The line output has a dedicated gain
stage that can be used to adjust the output level. The CHIP_LINE_OUT_VOL con-
trols the line level output gain.
The line outputs also have a dedicated mute that is controlled by the register field
CHIP_ANA_CTRL->MUTE_LO.
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SGTL5000 EA2 DS-0-3