WM8960CGEFLSLASHV datasheet(90/94 Pages) CIRRUS

90 / 94 page

WM8960

Rev 4.4

SPK+

SPK-

LOAD

CUTOFF = RLOAD/2*PI*L

CLASS D

-3dB

Figure 50 Speaker Equivalent Circuit

PCB LAYOUT CONSIDERATIONS

The efficiency of the speaker drivers is affected by the series resistance between the WM8960 and

the speaker (e.g. inductor ESR) as shown in Figure 51. This resistance should be as low as possible

to maximise efficiency.

VDD

GND

VMID

Losses due to resistance between WM8960 and speaker (e.g. inductor ESR)

This resistance must be minimised in order to maximise efficiency.

Switching

Losses

Class D

output

Figure 51 Speaker Connection Losses

The distance between the WM8960 and the speakers should be kept to a minimum to reduce series

resistance, and also to reduce EMI. Further reductions in EMI can be achieved by additional passive

filtering and/or shielding as shown in Figure 52. When additional passive filtering is used, low ESR

components should be chosen to minimise series resistance between the WM8960 and the speaker,

maximising efficiency.

LC passive filtering will usually be effective at reducing EMI at frequencies up to around 30MHz. To

reduce emissions at higher frequencies, ferrite beads placed as close to the device as possible will be

more effective.

Note:

Refer to the application note WAN_0118 on “Guidelines on How to Use QFN Packages and

Create Associated PCB Footprints”

WM8960CGEFL/V Datasheet(PDF) 90 Page - Cirrus Logic