WM8740

Advanced Information

WOLFSON MICROELECTRONICS LTD

AI Rev 1.7 July 2000

18

RECOMMENDED EXTERNAL COMPONENTS

28

DVDD

DGND

ML/I2S

AGND

AVDDL

AVDD

11

VMIDR

C

11

C

10

C

9

AGND

8

7

Software I/F or

Hardware Control

WM8740

Notes: 1.

AGND and DGND should be connected as close to the WM8740 as possible.

2.

C

3.

Capacitor type used can have a big effect on device performance. It is

recommended that capacitors with very low ESR are used and that ceramics are

either NPO or COG type material to achieve best performance from the WM8740.

AVDDR

AGNDR

AGNDL

C

3

C

4

C

5

C

6

AGND

C

2

DVDD

C

1

27

MC/DM1

26

MD/DM0

23

CSB/IWO

22

RSTB

12

MODE8X

6

DIFFHW

21

ZERO

AVDD

AVDD

R

1

18

VMIDL

C

12

1

LRCIN

2

DIN

3

BCKIN

5

SCLK

Audio Serial Data I/F

System Clock Input

DGND

+

+

+

+

15

9

20

14

10

19

24

MODE

25

MUTEB

VOUTRN

VOUTRP

-

-

+

+

13

12

LEFT OUTPUT DATA

RIGHT OUTPUT DATA

VOUTLP

17

VOUTLN

16

Figure 15 External Components Diagram

RECOMMENDED EXTERNAL COMPONENTS VALUES

COMPONENT

REFERENCE

SUGGESTED

VALUE

DESCRIPTION

C1 and C6

10

µF

De-coupling for DVDD and AVDD.

C2 to C5

0.1

µF

De-coupling for DVDD and AVDD.

C7 and C8

10

µF

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

C9 and C11

0.1

µF

C10 and C12

10

µF

Reference de-coupling capacitors for VMIDR and VMIDL.

R1

10k

Ω

Resistor to AVDD for open drain output operation.

Table 22 External Components Description