GSM Transceiver IC Uses Leading-Edge
High-Frequency Front End Technology
DuettoDC CXA3345GL
■ Four-Band support for
first time in the industry
· Four high-sensitivity
receiver LNA circuits
Sensitivity: –107 dBm
· Wide range VCO/PLL
circuits that support
all four bands
· Four-Band Low-Noise
High-Output Transmitter Modulator
■ Support for EDGE
transmission and reception
■ Fabricated in a highperformance 0.25 µm
SiGe BiCMOS process
■ Lead-free and halogen-free ultraminiature leadless package:
7 × 7 × 1.1 mm
Cellular phones are now used worldwide,
with GSM cellular phones having the
largest number of subscribers. GSM is
widely used in many countries in Europe,
North America, Asia, and Oceania. Last
year, Japan became an early adopter of
the W-CDMA third-generation cellular
phone. The third generation is expected
to see worldwide standardization.
Sony has developed many high-frequency
front-end products for these cellular
phone systems, including antenna
switches, power amplifiers, IF*1 amplifiers, RF*2 amplifiers, and RF transceivers (transmitter/receiver devices). Sony
has a proven track record as a first
vendor in this area, from first-generation
handsets through Japan’s W-CDMA
cellular phones. Sony devices are rated
highly by many handset manufacturers.
Sony has extensively analyzed the
question of what are desirable solutions
for GSM dual mode transceivers while
keeping the IMT-2000 standard
W-CDMA technique, which will become
the third generation worldwide unified
standard, in sight. The DuettoDC
CY 2001
CXA3320ER
GSM
CXM3000GA
module
CY 2002
CXA3345GL
DuettoDC
CXA3345GL introduced here is a
transceiver IC that adopts the latest
leading edge high-frequency front end
technology. Thus Sony provides an ideal
transceiver IC as a solution that aims to
create the leading handset in the GSM
cellular phone market, which is the
world’s largest cellular phone market.
Until now, GSM transceivers have
adopted the common superheterodyne
reception method and the sum loop
transmission method. The superheterodyne technique first converts the received
signal (RF) to an intermediate frequency
(IF) before extracting the baseband
signal. This means that two frequency
synthesizers, one for the RF signal and
one for the IF signal, are required. These
synthesizers are formed from VCO*3 and
PLL*4 circuits. However, since low phase
noise and high-speed locking are required
as the synthesizer performance, the usual
solution has been to develop these as
separate ICs.
Additionally, a SAW filter*5 is required
to acquire adequate IF frequency selectivity. Since it is difficult to integrate this
CY 2003
CY 2004
DuettoDC2
DuettoDC3
Customized
version
Customized
version
TI/Philips/Agere/ADI BB
Direct conversion
Quad LNA + PLL + VCO
DCR
For UMTS
Dual
mode
DM
For UMTS
RX IF
ASIC
CXA3328EN/
CXA3328TN
TX IF
ASIC
CXA3309ER/
CXA3329ER
W-CDMA
CXM4001GA/
CXM4002GA
TX/RX/PLL + VCO
module
DCR
DM
Direct conversion
■ Figure 1 GSM/3G (WCDMA/UMTS) IC Development Roadmap
DCR
Customized
version
DM
Customized
version
Harmony DC
GSM/UMTS
Dual mode
Zero-IF
(tentative)
DCR/DM
Low cost
transceiver
module
component on an IC chip, an external
component is used. Another issue is that
although the sum loop technique used for
transmission is effective at reducing transmission noise, it requires a power VCO
circuit in the output block for transmission.
To overcome these problems, Sony has
developed, for the CXA3345GL, both a
direct conversion receiver for the receiver
block and a direct modulation transmitter
for the transmitter block. These new approaches allowed Sony to create an ideal
GSM transceiver solution.
The GSM system for cellular phones is
the system used in the most regions worldwide. As long as you have a handset*6
that supports the frequency bands
allocated for the countries you will be
traveling to, travelers and businessmen
who go from country to country will be
able to use the same GSM cellular phone
they use in their home country in the same
way, i.e. with the same phone number. Up
to now, the main services have been the
900 MHz band and 1800 MHz band services used in Europe, Asia, and Oceania,
and the 1900 MHz band in North
America. The 850 MHz band service used
in the US has been added to this list. By
supporting all 4 of these bands, the
CXA3345GL supports all GSM cellular
phone frequency bands used worldwide.
IF: Intermediate frequency
RF: Radio frequency
VCO: Voltage controlled oscillator
PLL: Phase locked loop
SAW filter: Surface acoustic wave filter
New product: CXA3345GL
Conventional product:CXM3000GA
Package: LFLGA-60P-01
IF
SAW
LNA
1800
RF
SAW
LNA
900
RF
SAW
LNA
850
RF
SAW
LNA
Loop
filter
I
Q
CXA3345GL
VCO PLL
Div
1800/1900
Sum
RF
SAW
APC
RF
SAW
900
I
Sum
850
RF
SAW
LNA
RF
SAW
LNA
I
RF
SAW
Q
Div
LNA
monitor
Div
I
Loop
filter
RF
SAW
RF
SAW
Q
CXM3000G
Sum
Control
■ Figure 2 CXA3345GL Block Diagram
Q
RF VCO PLL1
IF VCO
PLL2
Base band
1900
RF
SAW
Base band
Easy SW
Package: VFLGA-84P-01
SW
*1
*2
*3
*4
*5
*6: There are several handsets, including dual
band (the 900 MHz/1800 MHz handset),
triple band (the 900 MHz/1800 MHz/1900
MHz handset), and quad band (the 850 MHz/
900 MHz/1800 MHz/1900 MHz handset),
and there are handsets that fit particular
uses, such as Europe-only handsets, or dual
Europe/USA handsets.
Four-Band Support for First
Time in the Industry
this device must support is an extremely
wide range spanning 1166 MHz.
To cover this range, the CXA3345GL includes an on-chip 4 GHz wideband VCO.
It also includes a ∆∑ PLL circuit that uses
a 26 MHz reference frequency. These circuits achieve both low phase noise and
high-speed locking while covering this
wide frequency range. The CXA3345GL
covers transmission and reception of all
four bands using a single VCO and a
single PLL circuits. Furthermore, the
high-speed frequency locking provides a
more than adequate control time for handling GPRS.
Four-Band High-Sensitivity
Reception LNA
Sony designed a new low noise amplifier
(LNA) with a noise figure of 3 dB
optimized for each band using a newlydeveloped high-performance SiGe
bipolar transistor (fTmax: 50 GHz,
NFmin: 0.7 dB), and achieved a reception sensitivity of –107 dBm.
Four-Band Wide Range
VCO/PLL
The lowest frequency used in any of the
four bands is the 824 MHz transmission
frequency used in the 850 MHz band, and
the highest frequency is the 1990 MHz
reception frequency used in the 1900
MHz band. Thus the frequency range that
Direct Conversion Receiver
In the CXA3345GL, the signal amplified
by the LNA is directly converted to a
baseband signal by the mixer circuit. This
obviates the need for the IF SAW filter
used in conventional products. The
CXA3345GL also includes circuits that
automatically correct the DC offset cancellation and the baseband filter cutoff.
This device provides stable reception
characteristics even when the gain is set
in 2 dB steps within the wide dynamic
range provided by the device. (See figures 3 and 4.)
Four-Band Low-Noise HighOutput Transmitter Modulator
The transmitter block also uses a direct
conversion technique, in particular, it converts the baseband signal directly using a
direct modulation technique. This obviates the need for the VCO used by the conventional sum loop technique. Direct
CF : 905 MHz
RBW : 30 kHz
VBW : 30 kHz
SWT : 5 ms
200 kHz : –35.9 dBc
400 kHz : –68.8 dBc
600 kHz : –74.1 dBc
–10
400 Ω
Differential
–20
200 Ω
Differential
40 kΩ
Minimum
–30
–40
–50
–60
–70
Input 1 dB compression point
(high gain mode 900 MHz)
Noise figure
Spec (typ.)
Measured
3.5 dB
2.4 dB
900 MHz
Spec (typ.)
Measured
3.5 dB
2.3 dB
1900 MHz
–20 dBm
–18 dBm
–80
–90
–100
–105
Center 900 MHz
■ Figure 3 Dynamic Range
200 kHz/
Span 2 MHz
■ Figure 5 GSM900 GMSK PN15 Transmit Mask
BB gain change
10
Output [dBm]
–20
–10
–30
–20
–40
–30
–50
–40
–60
–50
CF : 900 MHz
RBW : 30 kHz
VBW : 30 kHz
SWT : 6 ms
200 kHz : –38.6 dBc
400 kHz : –70.3 dBc
600 kHz : –77.3 dBc
–10
0
0
10
20
30
Gain setting
BB2/3 Gain step 2 ±0.2 dB
Spec
Measured (typ.)
±0.8
±0.4
■ Figure 4 Gain Steps
40
50
60
–70
–80
–90
–100
–105
Center 900 MHz
200 kHz/
Span 2 MHz
■ Figure 6 GSM900 EDGE Transmit Spectrum
modulation can also support EDGE transmission. (See figures 5, 6, and 7.)
Achievement of the No. 1 BoM
In designing the CXA3345GL, we
applied a wide range of benchmarks for
reducing the total number of external parts
in the parts list for the RF block, in
particular, looking at the question of
integrating which components would be
the most effective (due to their cost) at
reducing total cost. As a result, the
CXA3345GL holds the end product
BoM* 7 to extremely low levels by
integrating the VCO, PLL, and LNA
circuits on the same chip, and by
eliminating the IF SAW filter and the
transmitter power VCO components.
Thus the CXA3345GL is an extremely
cost-competitive RF block solution. (See
figures 8 and 9.)
Ultraminiature Leadless
Package
In addition to integrating the LNA, VCO,
and PLL circuits on the same chip, the
CXA3345GL is also provided in an
ultraminiature package with dimensions
of 7 × 7 × 1.1 mm. (See figure 10.) The
CXA3345GL uses 60 pins as electrical
signal lines, and provides 24 thermal
ground pins in the center of the package
for reduced thermal resistance. The package is an 84-pin VFLGA*8 package with
a land pitch of 0.65 mm. It also features
improved mounting strength lands at the
four corners. The materials used are both
lead free and halogen free, making the
CXA3345GL an environmentally
friendly RF block solution.
*8 VFLGA: Very Low Profile Fine Pitch Land
Grid Array
Future Developments
At the same time as developing multiple
versions to provide fine-grained support
for a wide range of handset types, Sony
will continue to aim for devices that
achieve even lower BoM levels. Sony will
also be working on the fusion of the GSM
and W-CDMA systems with dual mode
devices by developing and integrating
direct conversion receiver and direct
modulation transmitter circuits for
W-CDMA as well. Sony is currently
developing a W-CDMA power amplifier
module and a GSM power amplifier +
switch module. Sony is committed to
developing easy-to-use RF chip sets that
feature increased functionality and higher
integration levels based on compound
module technologies. Keep your eye on
Sony for your RF needs.
*7 BoM: Bill of Materials
IC
Mold
Chip
Interposer
VFLGA-84P-01
CXA3345GL
Standard EDGE
CF : 900 MHz
SR : 270.833 kHz
■ Figure 7 GSM900 EDGE Transmit Constellation
7 × 7 × 1.1 = 53.9 mm3
[Count]
60
[mA]
150
CXM3000GA
0
Sony
Company "A"
Company "B"
0
Sony
LCR Passive Active
■ Figure 8 RF Component BoM
Company "A"
Company "B"
RX TTL TX TTL
■ Figure 9
TX/RX Power
8 × 8 × 1.3 = 83.2 mm3
■ Figure 10 Ultraminiature Leadless
Package