User Guide

RH-17
System Module CCS Technical Documentation
Page 8 Nokia Corporation Confidential Issue 1 04/2003
Baseband Module
The core part of the RH-17 baseband module consists of three ASICs—UEM and UPP—
and flash memory. The following sections describe these parts.
UEM
UEM Introduction
UEM is the Universal Energy Management IC for DCT4 digital handportable phones. In
addition to energy management, it performs all the baseband mixed-signal functions.
Most of UEM pins have 2kV ESD protection. Those signals that are considered to be
exposed more easily to ESD have 8kV protection inside UEM. Such signals are all audio
signals, headset signals, BSI, Btemp, Fbus, and Mbus signals.
Regulators
UEM has six regulators for baseband power supplies and seven regulators for RF power
supplies. VR1 regulator has two outputs VR1a and VR1b.
Bypass capacitor (1uF) is required for each regulator output to ensure stability.
Reference voltages for regulators require external 1uF capacitors. Vref25RF is reference
voltage for VR2 regulator; Vref25BB is reference voltage for VANA, VFLASH1, VFLASH2,
VR1 regulators; Vref278 is reference voltage for VR3, VR4, VR5, VR6, VR7 regulators;