Keyboard interface
Figure 35 Keypad matrix
Backlight and illumination
The illumination has four main areas: numeric keypad (4 x white LEDs), functional keypad (UI) (2 x white
LEDs), display backlight (3 x white LEDs) and reminder light (1 x white LED). The display backlight is powered
by the integrated DC/DC converter of the Pearl/Gazoo IC. In addition to these LEDs, the two functional keypad
LEDs are powered via a current mirror from the Pearl/Gazoo.
The reminder LED is directly switched to VBAT via GENIO1. In the VLED+ line of the Pearl a “VLED disconnect
switch” is integrated. This avoids that the VLED line is at VBAT level even in switched off state (which can
cause electro migration problems).
RM-598; RM-604
System Module
Issue 1 COMPANY CONFIDENTIAL Page 5 –15
Copyright © 2009 Nokia. All rights reserved.
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