WM8741 Datasheet, PDF (36/66 Pages) Wolfson Microelectronics plc – 24-bit 192kHz DAC with Advanced Digital Filtering

WM8741
Production Data
DIFFERENTIAL MONO MODE
DIFF[1:0] sets the required differential output mode; normal stereo, reversed stereo, mono left or
mono right, as shown in Table 36.
REGISTER ADDRESS BIT LABEL
R8
[3:2] DIFF[1:0]
Mode Control 2
08h
Table 36 Differential Output Modes
DEFAULT
00
DESCRIPTION
00 = Stereo
10 = Stereo reverse (left and right
channels swapped)
01 = Mono left – differential outputs
VOUTLP (17) is left channel.
VOUTLN (16) is left channel
inverted.
VOUTRP (12) is left channel
inverted.
VOUTRN (13) is left channel.
11 = Mono right – differential outputs.
VOUTLP (17) is right channel
inverted.
VOUTLN (16) is right channel.
VOUTRP (12) is right channel.
VOUTRN (13) is right channel
inverted.
Using these controls a pair of WM8741 devices may be used to build a dual differential stereo
implementation with higher performance and differential output.
DITHER
Dither is applied whenever internal truncation occurs. It is also used when a 32 bit input word is
applied to the DAC prior to truncation to the internal wordlength. Three types of dither can be
selected to allow the sound quality if the device to be optimised.
TDF has a triangular probability density function and causes zero noise modulation i.e. the
quantisation noise is invariant to the changes in the signal level. This mode is recommended and is
selected by default.
RPDF has a rectangular probability density function and may cause noise modulation.
HPDF has a triangular probability density function with a high pass characteristic, which has a lower
noise at low frequencies at the expense of raised noise levels at higher frequencies.
Alternatively the dither can be disabled.
REGISTER ADDRESS BIT LABEL DEFAULT
DESCRIPTION
R8
[1:0] DITHER
10
Digital filter dither mode select:
Mode Control 2
[1:0]
00 = dither off
08h
01 = RPDF dither applied in Digital
filter
10 = TPDF dither applied in Digital
filter
11 = HPDF dither applied in Digital
filter
Note: DITHER[1:0] applies only to the
dither mode in the Digital filter.
Table 37 Dither Control
w
PD, Rev 4.3, February 2013
36