WM8750L Datasheet, PDF (45/56 Pages) Wolfson Microelectronics plc – STEREO CODEC FOR PORTABLE AUDIO APPLICATIONS

Product Preview
WM8750L
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.
REGISTER
ADDRESS
R24 (18h)
Additional Control
(2)
BIT
1
0
LABEL
DEFAULT
ADCOSR 0
DACOSR 0
Table 42 ADC and DAC Oversampling Rate Selection
DESCRIPTION
ADC oversample rate select
1 = 64x (lowest power)
0 = 128x (best SNR)
DAC oversample rate select
1 = 64x (lowest power)
0 = 128x (best SNR)
SAVING POWER AT LOW SUPPLY VOLTAGES
The analogue supplies to the WM8750L can run from 1.8V to 3.6V. By default, all analogue circuitry
on the device is optimized to run at 3.3V. This set-up is also good for all other supply voltages down
to 1.8V. However, at lower voltages, it is possible to save power by reducing the internal bias
currents used in the analogue circuitry. This is controlled as shown below.
REGISTER BIT LABEL DEFAULT
ADDRESS
DESCRIPTION
R23 (17h)
Additional
Control(1)
7:6 VSEL 11
[1:0]
Analogue Bias optimization
00: Lowest bias current, optimized for AVDD=1.8V
01: Low bias current, optimized for AVDD=2.5V
1X: Default bias current, optimized for AVDD=3.3V
PP Rev 1.77 May 2003
45