WM8711BL_07 Datasheet, PDF (29/43 Pages) Wolfson Microelectronics plc – Ultra-Small Audio DAC with Headphone Amplifier

Production Data
WM8711BL
128/192FS NORMAL MODE
The Normal Mode sample rates are designed for standard 256fs and 384fs MCLK rates. However the
WM8711BL is also capable of being clocked from a 128/192fs MCLK for application over limited
sampling rates as shown in the table below.
SAMPLING RATE
MCLK
DAC
FREQUENCY
SAMPLE
RATE
REGISTER SETTINGS
DIGITAL
FILTER
TYPE
kHz
MHz
BOSR SR3 SR2 SR1 SR0
48
6.144
0
0
1
1
1
2
9.216
1
0
1
1
1
44.1
5.6448
0
1
1
1
1
2
8.4672
1
1
1
1
1
Table 13 128/192fs Normal Mode Sample Rate Look-up Table
512/768FS NORMAL MODE
512fs and 768fs MCLK rates can be accommodated by using the CLKIDIV2 bit. The core clock to the
DSP will be divided by 2 so an external 512/768 MCLK will become 256/384fs internally and the
device otherwise operates as in Table 9 but with MCLK at twice the specified rate.
USB MODE SAMPLE RATES
In USB mode the MCLK input is 12MHz only.
SAMPLING RATE
MCLK
DAC
FREQUENCY
SAMPLE
RATE
REGISTER SETTINGS
DIGITAL
FILTER
TYPE
kHz
MHz
BOSR SR3 SR2 SR1 SR0
48
12.000
0
0
0
0
0
0
44.1
(Note 2)
8
12.000
1
1
0
0
0
1
12.000
0
0
0
0
1
0
8
(Note 1)
32
12.000
1
1
0
0
1
1
12.000
0
0
1
1
0
0
96
12.000
0
0
1
1
1
3
88.2
12.000
1
1
1
1
1
2
(Note 3)
Table 14 USB Mode Sample Rate Look-Up Table
Notes:
1. 8k not exact, actual = 8.021kHz
2. 44.1k not exact, actual = 44.118kHz
3. 88.1k not exact, actual = 88.235kHz
4. All other combinations of BOSR and SR[3:0] that are not in the truth table are invalid
The BOSR bit represents the base over-sampling rate. This is the rate that the WM8711BL digital
signal processing is carried out at and the sampling rate will always be a sub-multiple of this. In USB
mode, with BOSR = 0, the base over-sampling rate is defined at 250Fs, with BOSR = 1, the base
over-sampling rate is defined at 272Fs. This can be used to determine the actual audio sampling rate
required by the DAC.
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PD, Rev 4.1, April 2007
29