Table of Contents
Advertisement
RA-2/3
7 - RF Description and Troubleshooting
Nokia Customer Care
DC characteristics
Regulators
The transceiver baseband section has a multi function analog ASIC, UEM, which contains
among other functions six pieces of 2.78 V linear regulators and a 4.8 V switching regulator. All
the regulators can be controlled individually by the 2.78 V logic directly or through a control reg-
ister. Normally, direct control is needed because of switching speed requirement: the regula-
tors are used to enable the RF-functions which means that the controls must be fast enough.
The use of the regulators can be seen in the power distribution diagram which is presented in
Figure 6, "Power distribution diagram," on page 15.
The seven regulators are named VR1 to VR7. VrefRF01 is used as a reference voltage for
Helgo.
The regulators (except for VR7) are connected to the Helgo. Different modes of operation can
be selected inside the Helgo according to the control information coming through the RFBus.
DC supply currents
Figure 5: DC power supplies
Issue 1 09/04
COMPANY CONFIDENTIAL
13
Copyright © 2004 Nokia. All Rights Reserved.
Advertisement
Table of Contents
Troubleshooting
