WM8750L
Production Data
REGISTER
ADDRESS
BIT
LABEL
OUT3
DEFAULT
DESCRIPTION
OUT3 Output Buffer
1
0
0 = Power down
1 = Power up
* The left mixer is enabled when LOUT1=1 or LOUT2=1. The right mixer is enabled when
ROUT1=1 or ROUT2=1.
Table 43 Power Management
STOPPING THE MASTER CLOCK
In order to minimise power consumed in the digital core of the WM8750L, the master clock may be
stopped in Standby and OFF modes. If this cannot be done externally at the clock source, the
DIGENB bit (R25, bit 0) can be set to stop the MCLK signal from propagating into the device core. In
Standby mode, setting DIGENB will typically provide an additional power saving on DCVDD of 20uA.
However, since setting DIGENB has no effect on the power consumption of other system components
external to the WM8750L, it is preferable to disable the master clock at its source wherever possible.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R25 (19h)
DIGENB
Master clock disable
0
0
Additional Control
(1)
0: master clock enabled
1: master clock disabled
Table 44 Master Clock Disable
Note: Before DIGENB can be set, the control bits ADCL, ADCR, DACL and DACR must be set to
zero and a waiting time of 1ms must be observed. Any failure to follow this procedure may prevent
DACs and ADCs from re-starting correctly.
SAVING POWER BY REDUCING OVERSAMPLING RATE
The default mode of operation of the ADC and DAC digital filters is in 128x oversampling mode.
Under the control of ADCOSR and DACOSR the oversampling rate may be halved. This will result in
a slight decrease in noise performance but will also reduce the power consumption of the device. In
USB mode ADCOSR must be set to 0, i.e. 128x oversampling.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R24 (18h)
ADCOSR
ADC oversample rate select
1 = 64x (lowest power)
0 = 128x (best SNR)
1
0
Additional Control
(2)
DACOSR
DAC oversample rate select
1 = 64x (lowest power)
0 = 128x (best SNR)
0
0
Table 45 ADC and DAC Oversampling Rate Selection
ADCOSR set to ‘1’, 64x oversample mode, is not supported in USB mode (USB=1).
PD, Rev 4.4, August 2012
52
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
