User Guide

NPL-4/5

System Module and User Interface Nokia Customer Care

DC characteristics

Regulators

The transceiver baseband section has a multi function analog ASIC, UEMEK, which con-

tains 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 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 seven regulators are named VR1 to VR7. VrefRF01 is used as the reference voltages

for the Helgo, VrefRF01 (1.35V) for the bias reference and for the RX ADC (analog-to-

digital converter) reference.

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.

List of the needed supply voltages

Volt. source Load

VR1 PLL charge pump (4.8 V)

VR2 TX modulators, ALCs, driver

VR3 VCTCXO, synthesizer digital parts

VR4 Helgo pre-amps, mixers, DtoS

VR5 dividers, LO-buffers, prescaler

VR6 LNAs, Helgo baseband (Vdd_bb)

VR7 VCO

VrefRF01 ref. voltage for Helgo

Vbatt PA