WM8524
Production Data
Figure 8 I2S Justified Audio Interface (assuming n-bit word length)
DIGITAL AUDIO DATA SAMPLING RATES
The external master clock is applied directly to the MCLK input pin. In a system where there are a
number of possible sources for the reference clock, it is recommended that the clock source with the
lowest jitter be used for the master clock to optimise the performance of the WM8524.
The WM8524 has a detection circuit that automatically determines the relationship between the
master clock frequency (MCLK) and the sampling rate (LRCLK), to within ±32 system clock periods.
The MCLK must be synchronised with the LRCLK, although the device is tolerant of phase variations
or jitter on the MCLK.
If during sample rate change the ratio between MCLK and LRCLK varies more than once within 1026
LRCLK periods, then it is recommended that the device be taken into the standby state or the off
state before the sample rate change and held in standby until the sample rate change is complete.
This will ensure correct operation of the detection circuit on the return to the enabled state. For details
on the standby state, please refer to the Power up and down control section of the datasheet on page
16.
The DAC supports MCLK to LRCLK ratios of 128fs to 1152fs and sampling rates of 8kHz to 192kHz.
Table 3 shows typical master clock frequencies and sampling rates supported by the WM8524 DAC.
MASTER CLOCK FREQUENCY (MHz)
Sampling Rate
LRCLK
128fs
Unavailable
Unavailable
Unavailable
Unavailable
11.2896
192fs
Unavailable
Unavailable
Unavailable
Unavailable
16.9344
256fs
2.048
384fs
3.072
512fs
4.096
768fs
6.144
1152fs
9.216
8kHz
32kHz
8.192
12.288
16.384
24.576
36.864
44.1kHz
48kHz
11.2896
12.288
16.9344
18.432
22.5792
33.8688
Unavailable
Unavailable
Unavailable
Unavailable
Unavailable
Unavailable
24.576
36.864
88.2kHz
96kHz
22.5792
24.576
33.8688
36.864
Unavailable
Unavailable
Unavailable
Unavailable
Unavailable
Unavailable
Unavailable
Unavailable
12.288
18.432
176.4kHz
192kHz
22.5792
33.8688
Unavailable
Unavailable
Unavailable
Unavailable
24.576
36.864
Table 3 MCLK Frequencies and Audio Sample Rates
PD, Rev 4.1, October 2011
14
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
