WM8722

Advanced Information

WOLFSON MICROELECTRONICS LTD

AI Rev 1.5 May 2000

22

RECOMMENDED EXTERNAL COMPONENTS

2

DVDD

DGND

MC

AGND

AVDD

CAP

C

12

C

11

AGND

6

16

SPI or 2-wire

Interface

WM8722

NOTES:

1. AGND and DGND should be connected as close to the WM8722 as possible.

2. C

2

, C

3

, C

9

, C

10

and C

11

should be positioned as close to the WM8722 as possible.

3. Capacitor types should be carefully chosen. Capacitors with very low ESR are

recommended for optimum performance.

C

3

C

4

C

2

DVDD

C

1

3

MD

4

LATCH

VAROUTR

12

C

5

VAROUTL

C

6

AC-Coupled

Variable Outputs

to External LPF

9

AVDD

1

TCLK

17

DIN

18

LRCIN

20

SCKI

Audio Serial Data I/F

DGND

AGND

LINEOUTR

13

C

7

LINEOUTL

C

8

AC-Coupled

Line Level outputs

to External LPF

8

5

BUSY

19

BCKIN

11

10

+

15

+

+

7

MIXINR

14

MIXINL

C

9

C

10

2-wire Interface

SPI Interface

DVDD

DGND

R1

Figure 11. External Components Diagram

RECOMMENDED EXTERNAL COMPONENTS VALUES

COMPONENT

REFERENCE

SUGGESTED

VALUE

DESCRIPTION

C1 and C4

10

µF

De-coupling for DVDD and AVDD.

C2 and C3

0.1

µF

De-coupling for DVDD and AVDD.

C5, C6, C7 and C8

10

µF

Output AC coupling caps to remove midrail DC level from outputs.

C11

0.1

µF

C12

10

µF

Reference de-coupling capacitors for CAP pin.

R1

10k

Ω

C9,C10

1

µF

AC coupling capacitors for setting DC inputs level of analogue

Table 11. External Components Description