PCM5121_16 Datasheet, PDF (60/120 Pages) Texas Instruments – Audio Stereo DAC

PCM5121, PCM5122
SLAS763B – AUGUST 2012 – REVISED JANUARY 2016
10 Power Supply Recommendations
10.1 Power Supply Distribution and Requirements
The PCM512x devices are powered through the pins shown in Figure 77.
AVDD 3.3V
CPVDD 3.3V
DVDD (1.8V or 3.3v)
LDOO 1.8V
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DAC
Reference
PLL
Line Driver
Charge Pump
Oscillator
Digital IO
1.8V LDO
Digital Core
( ^W[•, Logic etc)
Clock Halt Detect
Analog Circuits
Digital Circuits
Power Circuits
PCM186x
Figure 77. Power Distribution Tree Within PCM512x
NAME
AVDD
DVDD
CPVDD
LDOO
AGND
DGND
Table 46. Power Supply Pin Descriptions
USAGE / DESCRIPTION
Analog voltage supply; must be 3.3 V. This powers all analog circuitry that the DAC runs on.
Digital voltage supply. This is used as the I/O voltage control and the input to the onchip LDO.
Charge Pump Voltage Supply - must be 3.3 V
Output from the onchip LDO. Should be used with a 0.1-µF decoupling cap. Can be driven (used as power
input) with a 1.8-V supply to bypass the onchip LDO for lower power consumption.
Analog ground
Digital ground
10.2 Recommended Powerdown Sequence
Under certain conditions, the PCM512x devices can exhibit some pops on power down. Pops are caused by a
device not having enough time to detect power loss and start the muting process.
The PCM512x devices have two auto-mute functions to mute the device upon power loss (intentional or
unintentional).
10.2.1 XSMT = 0
When the XSMT pin is pulled low, the incoming PCM data is attenuated to 0, closely followed by a hard analog
mute. This process takes 150 sample times (t_s) + 0.2 ms.
Because this mute time is mainly dominated by the sampling frequency, systems sampling at 192 kHz will mute
much faster than a 48-kHz system.
10.2.2 Clock Error Detect
When clock error is detected on the incoming data clock, the PCM512x devices switch to an internal oscillator,
and continue to the drive the output, while attenuating the data from the last known value. Once this process is
complete, the PCM512x outputs are hard muted to ground.
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