wm8987 Wolfson Microelectronics plc, wm8987 Datasheet - Page 44

• Manufacturer Part Number: wm8987
• Description: Stereo Codec For Portable Audio Applications
• Manufacturer: Wolfson Microelectronics plc

WM8987L
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POWER SUPPLIES
The WM8987L has two possible device addresses, which can be selected using the CSB pin.
Table 40 2-Wire MPU Interface Address Selection
The WM8987L 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.
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 the headphone drivers. HPVDD is normally tied
to AVDD, but it 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 4.0 August 2008
Production Data
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