wm8400 Wolfson Microelectronics plc, wm8400 Datasheet - Page 91

• Manufacturer Part Number: wm8400
• Description: Wolfson Audioplustm Hi-fi Audio Codec And Power Management Unit For Mobile Multimedia
• Manufacturer: Wolfson Microelectronics plc

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Pre-Production
The output mixers ROPMIX and RONMIX and their outputs ROP and RON are controlled as
described in Table 57. Care should be taken to avoid clipping when enabling more than one path to
ROP or RON. The ROATTN attenuation control can be used to prevent clipping when more than one
full scale signal is input to the ROP mixer.
Table 57 ROP and RON Volume Control
ANALOGUE BIAS OPTIMISATION
The AVDD supply of the WM8400 can operate between 2.7V and 3.6V. By default, all analogue
circuitry on the device is optimised to run at 3.0V.
At lower voltages, an increased bias current may be selected. The default bias current may still be
used (for lower power operation), but this may result in degraded performance of the outputs OUT3,
OUT4, LOUT and ROUT. The bias current is controlled as shown in Table 58.
Table 58 Bias Optimisation
R30 (1Eh)
R53 (35h)
R51 (33h)
REGISTER
ADDRESS
REGISTER
ADDRESS
8:7
BIT
BIT
2
1
0
6
5
4
2
1
0
VSEL
[1:0]
LABEL
RONMUTE
ROPMUTE
ROATTN
RROPGARON
RLOPGARON
ROPRON
RL12ROP
RR12ROP
RROPGAROP
LABEL
11
DEFAULT
DEFAULT
1b
1b
0b
0b
0b
0b
0b
0b
0b
Analogue Bias Optimisation
00 = Reserved
01 = Bias current optimised for AVDD=2.7V
1X = Bias current optimised for AVDD=3.0V
0 = Un-mute
1 = Mute
ROP Line Output Mute
0 = Un-mute
1 = Mute
ROP Attenuation
0 = 0dB
1 = -6dB
0 = Mute
1 = Un-mute
0 = Mute
1 = Un-mute
0 = Mute
1 = Un-mute
LIN12 PGA Output to ROPMIX
0 = Mute
1 = Un-mute
RIN12 PGA Output to ROPMIX
0 = Mute
1 = Un-mute
0 = Mute
1 = Un-mute
RON Line Output Mute
ROPGA to RONMIX
LOPGA to RONMIX
Inverted ROP Output to RONMIX
ROPGA to ROPMIX
DESCRIPTION
DESCRIPTION
PP, April 2009, Rev 3.0
WM8400
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