User Guide

ALS interface

Ambient Light Sensor consists following components:

• Lightguide (part of A-cover)

• Ambient Light Sensor (ALS). ALS is logarithmic, which response to light is similar to human eye. ALS is

located on UI-FPC and it is not a spare part

• Analog switch N4503, to turn on operating voltage VAUX to ALS only when needed (located on system/ RF

module)

• Pull-down resistor R4505 to convert current signal to voltage (located on system/ RF module)

Ambient Light Sensor information is used to control cover backlights of the phone. Cover keyboard backlight

is turned OFF, when they are not needed.

Cover display backlight is dimmed, when environment lighting is dark. Ambient Light Sensor is calibrated in

production. In service points, calibration is not possible.

ASICs

RAP ASIC

RAP ASIC is a 3G Radio Application Processor. RAM memory is integrated into RAP.

EM ASIC N2300

The EM ASIC (N2300) includes the following functional blocks:

• Core supply generation

• Charge control circuitry

• Level shifter and regulator for USB/FBUS

• Current gauge for battery current measuring

• LED driver for backlights

• Digital interface (CBUS)

EM ASIC N2200

The EM ASIC (N2200) includes the following functional blocks:

• Start up logic and reset control

• Charger detection

• Battery voltage monitoring

RA-6

System Module

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