Audio Codec (AC)
User Manual All information provided in this document is subject to legal disclaimers. © REALTEK 2019. All rights reserved.
333
ADC channel variation
L vs. R variation
±0.2
dBFS
Analog supply voltage (AVCC)
1.70
2.8
3.0
V
MIC bias
AVCC=2.8V
AVCC*0.75
AVCC*0.9
V
AVCC=1.7V
1.5V
Digital supply voltage (DVDD)
0.99
1.1
1.21
V
17.5
Application and Implementation
17.5.1
Audio Output
Ameba-D audio codec supports three output modes: cap-less, differential and single-end. You can select a mode by setting the related
registers. There are some differences in board circuit design among these modes.
17.5.1.1
Line-out Cap-less Mode
In this mode, the N-end of L/R channel outputs common-level voltage, while P-end drives the available analog audio signal. When earphone
inserts into the jack, the ground must short with N-end output for audio signal de-couple. This is the reason that the ground is called virtual
ground. The cap-less mode connection with a headphone jack is shown in Fig 17-2.
Ameba-D
MICBIAS
MIC_P
LOUT_P
ROUT_P
ROUT_N
LOUT_N
g
m/g
s
s
g = virtual ground
m = mic
s = ear speaker
Fig 17-2 Cap-less mode connection with headphone jack
17.5.1.2
Line-out Differential Mode
In this mode, both N-end and P-end drive the available analog audio signal. Users should select the differential jack and earphone accordingly.
The differential mode connection with a headphone jack is shown in Fig 17-3.
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2019-05-15 10:08:03