WM8971L Wolfson Microelectronics Ltd., WM8971L Datasheet - Page 47

• Manufacturer Part Number: WM8971L
• Description: Stereo Codec for Portable Audio Applications
• Manufacturer: Wolfson Microelectronics Ltd.

Production Data
w
POWER SUPPLIES
POWER MANAGEMENT
The WM8971L has two possible device addresses, which can be selected using the CSB pin.
Table 38 2-Wire MPU Interface Address Selection
The WM8971L can use up to four separate power supplies:
•
•
•
•
It is possible to use the same supply voltage on all four. However, digital and analogue supplies
should be routed and decoupled separately to keep digital switching noise out of the analogue signal
paths.
The WM8971L has two control registers that allow users to select which functions are active. For
minimum power consumption, unused functions should be disabled. To avoid any pop or click noise,
it is important to enable or disable functions in the correct order (see Applications Information).
VMIDSEL is the enable for the Vmid reference, which defaults to disabled and can be enabled as a
50kOhm potential divider or, for low power maintenance of Vref when all other blocks are disabled,
as a 500kOhm potential divider.
CSB STATE
AVDD / AGND: Analogue supply, powers all analogue functions except the headphone drivers.
AVDD can range from 1.8V to 3.6V and has the most significant impact on overall power
consumption (except for power consumed in the headphone). A large AVDD slightly improves
audio quality.
HPVDD / HPGND: Headphone supply, powers analogue outputs L/ROUT1, L/ROUT2 and
MONOOUT. HPVDD is normally tied to AVDD, but requires separate layout and decoupling
capacitors to curb harmonic distortion. If HPVDD is lower than AVDD, the output signal may be
clipped.
DCVDD: Digital core supply, powers all digital functions except the audio and control
interfaces. DCVDD can range from 1.42V to 3.6V, and has no effect on audio quality. The
return path for DCVDD is DGND, which is shared with DBVDD.
DBVDD: Digital buffer supply, powers the audio and control interface buffers. This makes it
possible to run the digital core at very low voltages, saving power, while interfacing to other
digital devices using a higher voltage. DBVDD draws much less power than DCVDD, and has
no effect on audio quality. DBVDD can range from 1.8V to 3.6V. The return path for DBVDD is
DGND, which is shared with DCVDD.
High
Low
DEVICE ADDRESS
0011010 (0 x 34h)
0011011 (0 x 36h)
PD Rev 4.1 August 2005
WM8971L
47