WM8734SEFL Wolfson Microelectronics, WM8734SEFL Datasheet - Page 28

• Manufacturer Part Number: WM8734SEFL
• Description: Audio CODECs Stereo CODEC
• Manufacturer: Wolfson Microelectronics

Specifications of WM8734SEFL

• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: QFN-28
• Minimum Operating Temperature: - 25 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

WM8734
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Uniquely, the WM8734 offers the user the ability to sample the ADC and DAC at different rates under
software control in both Normal and USB modes. The reduces the burden on any controlling DSP.
However, the signal processing in the ADC and DAC over-sampling filters is tightly coupled together
in order to minimise power consumption. To this end, only the combinations of sample rates listed in
the following sections are supported. Note that these rates supported are anticipated to be the likely
combinations used in typical audio systems.
Table 9 Sample Rate Control
SAMPLE RATE SETTING
In normal mode MCLK/crystal oscillator is set up according to the desired sample rates of the ADC
and DAC. For ADC or DAC sampling rates of 8, 32, 48 or 96kHz, MCLK frequencies of either
12.288MHz (256fs) or 18.432MHz (384fs) can be used. For ADC or DAC sampling rates of 8, 44.1 or
88.2kHz from MCLK frequencies of either 11.2896MHz (256fs) or 16.9344MHz (384fs) can be used.
The table below should be used to set up the device to work with the various sample rate
combinations. For example if the user wishes to use the WM8734 in normal mode with the ADC and
DAC sample rates at 48kHz and 48kHz respectively then the device should be programmed with
BOSR = 0, SR3 = 0, SR2 = 0, SR1 = 0 and SR0 = 0 with a 12.288MHz MCLK or with BOSR = 1,
SR3 = 0, SR2 = 0, SR1 = 0 and SR0 = 0 with a 18.432MHz MCLK. The ADC and DAC will then
operate with a Digital Filter of type 1, refer to Digital Filter Characteristics section for an explanation
of the different filter types.
0001000
Sampling
Control
REGISTER
ADDRESS
0
1
5:2
BIT
USB/
NORMAL
BOSR
SR[3:0]
LABEL
0
0
0000
DEFAULT
Mode Select
1 = USB mode (250/272fs)
0 = Normal mode (256/384fs)
Base Over-Sampling Rate
USB Mode
0 = 250fs
1 = 272fs
ADC and DAC sample rate control;
See USB Mode and Normal Mode
Sample Rate sections for operation
DESCRIPTION
PD, Rev 4.3, January 2009
Normal Mode
96/88.2 kHz
0 = 256fs
0 = 128fs
1 = 384fs
1 = 192fs
Production Data
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