WM8991 datasheet(10/174 Pages) WOLFSON

Part #	WM8991

Description	Mobile Multimedia CODEC with Dual-Mode Class AB/D Speaker Driver

PDF	174 Pages

Scroll/Zoom	100%

Manufacturer	WOLFSON [Wolfson Microelectronics plc]

Direct Link	http://www.wolfsonmicro.com

Logo

10 / 174 page

WM8991

Pre-Production

PP, May 2008, Rev 3.1

SPEAKER POWER DE-RATING CURVE

The speaker driver has been designed to drive a maximum of 1W into 8

Ω with a 5V supply.

However, thermal restrictions defined by the BGA package ӨJA limit the amount of power that can be

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.

CLASS D DE-RATING CURVES

The de-rating curves shown in Figure 2 are based on a full scale sinusoidal input.

[W]

[ºC]

0.4

0.6

0.8

1.0

SPKVDD = 2.7V

SPKVDD = 3V

SPKVDD = 3.3V

SPKVDD = 3.6V

SPKVDD = 4.2V

SPKVDD = 5V

SPKVDD = 5.5V

0.9

0.7

0.3

0.5

0.1

0.2

Figure 2 Class D Speaker Power De-Rating Curve

WM8991 Datasheet(PDF) 10 Page - Wolfson Microelectronics plc