wm9001 Wolfson Microelectronics plc, wm9001 Datasheet - Page 7

• Manufacturer Part Number: wm9001
• Description: 1w Dual-mode Class Ab/d Speaker Driver
• Manufacturer: Wolfson Microelectronics plc

Pre-Production
POWER DE-RATING
w
The speaker driver has been designed to drive a maximum of 1W into 8Ω with a 5V supply.
However, thermal restrictions defined by the package Ө
safely dissipated in the device without exceeding the maximum operating junction temperature.
Power dissipated in the device correlates directly with speaker efficiency, hence there are separate
de-rating curves for class D and class AB operation.
Under no circumstances should the recommended maximum powers be exceeded.
The de-rating curves in Figure 1 are based on a sinusoidal input signal delivering a maximum output
power of 1W into 8Ω.
[W]
P
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
Figure 1 Speaker Power De-Rating Curves
SPKVDD = 5.5V
SPKVDD = 3.6V
SPKVDD = 3.3V
SPKVDD = 2.7V
SPKVDD = 3V
SPKVDD = 5V
CLASS AB
CLASS D
55
60
SPKVDD = 4.2V
65
70
75
80
85
JA
limit the amount of power that can be
[ºC]
T
PP, June 2009, Rev 3.2
WM9001
7