User Guide

RM-11
System Module CC Technical Documentation
Page 28 ©2004 Nokia Corporation Confidential Issue 1 02/2004
Figure 24: BB_RF interface connections (4)
RF Functional Description
Most of the RF functions are centered around the RF ASIC. Receiver IF stages, low-band
LNA, PLLs, RXVHF oscillator, TX VHF VCO active part and loop filter, high-band and low-
band TX up-converters, TX IF stages, IQ modulator and demodulator and reference oscil-
lator buffering are all integrated on single chip.
Circuit Diagrams and PWB Layout
Receiver
The receiver design and system partition is from the Snoopy AD project. The receiver
shows a superheterodyne structure with zero 2nd IF. Low-band and high-band receivers
have separate front ends from the diplexer to the first IF. Most of the receiver functions
are integrated in the RF ASIC. The only functions out of the chip are the high-band LNA,
duplexers, and SAW filters. Receiver characteristics are very similar on both bands.
An active first downconverter sets naturally high-gain requirements for preceding
stages. Losses in very selective front-end filters are minimized down to the limits set by
filter technologies used and component sizes. The LNA gain is set up to 16 dB, which is
close to the maximum available stable gain from a single-stage amplifier. LNAs are not
exactly noise matched in order to keep pass band gain ripple to a minimum. Filters have
relatively tight stop band requirements, which are not all set by the system requirements
VRF Globals instead of Bus Regulated RF Supply Voltages from UEM to RF. Current values are of the
regulator specifications, not the measured values of RF
VR1 A UEM RFIC
Out Vreg
4.75 V
+- 3 %
10 mA max. UEM, charge pump + linear regulator
output. Supply for UHF synth phase det ….
VR1 B UEM RFIC
Out Vreg
4.75 V
+- 3 %
10 mA max. UEM, charge pump + linear regulator
output.
VR2 UEM RFDiscr./
RFIC
Out Vreg
2.78 V
+- 3 %
100 mA max. UEM linear regulator. Supply voltage for Tx
IQ filter and IQ to Tx IF mixer.
VR3 UEM VCTCXO
Out Vreg
2.78 V
+- 3 %
20 mA max. UEM linear regulator. Supply for VCTCXO +
RFCLK Buffer in RF IC.
VR4 UEM RFIC
Out Vreg
--”-- 50 mA max. UEM linear regulator. Power Supply for LNA
/ RFIC Rx chain.
VR5 UEM RFIC
Out Vreg
--”-- 50 mA max. UEM linear regulator. Power Supply for RF
low band PA driver section.
VR6 UEM RFIC
Out Vreg
--”-- 50 mA max. UEM linear regulator. Power supply for RF
high band PA driver section.
VR7 UEM RFIC,
UHF VCO
Out Vreg
--”-- 45mA UEM linear regulator. Power supply for RF
Synths
IPA1 UEM RF PA
Out Iout
0-5 mA Settable Bias current for RF PA L-Band
IPA2 UEM RFPA
Out Iout
0-5 mA Settable Bias current for RF PA H-band
VFLASH1 UEM RFIC
Out Iout
2.78V ~2mA UEM linear regulator common for BB.
RFIC digital parts and RF to BB digi IF.
VBATT, Global
VBATTRF Batt
Conn
RFPA
Out Vbatt
3…5V 0…1A
2A peak
Raw Vbatt for RF PA