Nokia 6610i Service Manual

RM-37

Company confidential

7-System Module and User Interface

CCS Technical Documentation

Page 46

  ©Nokia Corporation.

Issue 1  04/2004

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 regu-
lator. All the regulators can be controlled individually by the 2.78 V logic directly or 
through a control register. Normally, direct control is needed because of switching speed 
requirement: the regulators 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 pre-
sented in Figure 20, “Power distribution diagram,” on page 48.

The seven regulators are named VR1 to VR7. VrefRF01 and VrefRF02 are used as the ref-
erence voltages for the Helga, VrefRF01 (1.35V) for the bias reference and VrefRF02 
(1.35V) for the RX ADC (analog-to-digital converter) reference.

The regulators (except for VR7) are connected to the Helga. Different modes of operation 
can be selected inside the Helga according to the control information coming through 
the RFBus.

List of the needed supply voltages

VR1

PLL charge pump (4.8 V)

VR2

TX modulators, ALCs, driver

VR3

VCTCXO, synthesizer digital parts

VR4

Helga pre-amps, mixers, DtoS

VR5

dividers, LO-buffers, prescaler

VR6

LNAs, Helga baseband (Vdd_bb)

VR7

VCO

VrefRF01

ref. voltage for Helga

VrefRF02 

ref. voltage for Helga

Vbatt

PA