WM8903LGEFK/RV Wolfson Microelectronics, WM8903LGEFK/RV Datasheet - Page 90

• Manufacturer Part Number: WM8903LGEFK/RV
• Description: Audio CODECs ULTRA LOW PWR HI FI CODEC
• Manufacturer: Wolfson Microelectronics

Specifications of WM8903LGEFK/RV

• Audio Codec Type: Stereo Codec
• No. Of Adcs: 2
• No. Of Dacs: 2
• No. Of Input Channels: 6
• No. Of Output Channels: 8
• Adc / Dac Resolution: 24bit
• Sampling Rate: 96kHz
• Operating Temperature Range: -40°C To +85°C
• Rohs Compliant: Yes
• Adcs / Dacs Signal To Noise Ratio: 96dB
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

WM8903
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Table 62 Sample Rate Decoder Control
The clock division ratios available with CLK_SYS_MODE = 00 are suitable for use with standard
audio master clocks. For example, with a 12.288MHz CLK_SYS and 48kHz sample rate, the
CLK_SYS to fs ratio is 256. In this case, the required setting for CLK_SYS_RATE is 0011, as shown
above.
USB MODE
Other settings of CLK_SYS_MODE allow compatibility with a USB clock, at sample rates of up to
48kHz. For example, with a 12MHz (USB) clock and an 8kHz sample rate, the CLK_SYS to fs ratio is
1500. In this case, the required setting for CLK_SYS_RATE is 1001.
Note that 44.1kHz and related sample rates are approximate when derived from a USB clock. For
example, with a 12MHz MCLK and a division ratio of 272, the exact sample rate obtained is
44.118Hz rather than 44.1kHz. This 0.04% offset is inaudible and can be ignored. 48kHz and related
sample rates are exact in all modes of operation, provided that MCLK itself is exact.
DIGITAL MICROPHONE
When GPIO1/DMIC_LR is configured as DMIC_LR Clock output, the WM8903 outputs a clock which
supports Digital Microphone operation at a multiple of the ADC sampling rate. The precise clock
frequency varies according to the MCLK frequency, the SAMPLE_RATE field and other settings. The
clock frequency is always within the range 1MHz - 3MHz, and some examples are shown in Table
63.
Table 63 Digital Microphone Clock
Note that the 88.2kHz and 96kHz sample rate settings are not valid for Digital Microphone operation.
SAMPLE
44.1kHz
44.1kHz
16kHz
16kHz
48kHz
48kHz
32kHz
24kHz
12kHz
RATE
8kHz
8kHz
1010 to 1111
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
Available CLK_SYS / f
11.2896MHz
12.288MHz
12.288MHz
12.288MHz
CLK_SYS
12MHz
12MHz
12MHz
12MHz
12MHz
12MHz
12MHz
1024
1408
1536
128
192
256
384
512
768
00
64
CLK_SYS_MODE
Reserved
s
1088
1496
1632
136
204
272
408
544
816
ratios
01
68
CLK_SYS
1536fs
1500fs
1000fs
RATIO
768fs
750fs
256fs
250fs
256fs
272fs
375fs
500fs
10 or 11
1000
1000
1500
125
125
250
250
375
500
750
FREQUENCY
1.024MHz
2.048MHz
1.536MHz
2.400MHz
2.822MHz
3.000MHz
2.400MHz
2.400MHz
1.200MHz
2.400MHz
1.500MHz
DMIC_LR
DMIC_LR RATIO
PP, Rev 3.1, August 2009
128fs
150fs
128fs
150fs
100fs
125fs
32fs
50fs
64fs
68fs
75fs
Pre-Production
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