User Guide

NHM–7

System Module & UI

PAMS Technical Documentation

Page 39

Issue 1 10/2001

 Nokia Corporation

LEDs are controlled by the UEM PWM outputs. Both LEDs are controlled

KLight

output of the UEM. Current flow through the LEDS is set by

biasing the transistor and limiting the current by resistors. Current is set

separately to keyboard and LCD leds.

Internal Speaker

The internal earpiece is a dynamic earpiece with an impedance of 32

ohms. The earpiece is low impedance one since the sound pressure is to

be generated using current and not voltage as the supply voltage is re-

stricted to 2.7V. The earpiece is driven directly by the UEM and the ear-

piece driver in UEM is a bridge amplifier.

1000Ω@100MHz

22Ω

EARP

EARN

UEM

27pF 27pF