Front End Module and Filter Device Technology

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Front End Module and Filter Device
Technology Rich Ruby Director of Technologies
Avago Technologies
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Many people believe that Silicon will consume all
the functions in future mobile devices But,
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Drivers for improved performance in FEM
Components Example 1
Service providers are demanding that the talk
time of CDMA and UMTS phones equal that of the
GSM phones. At the same time, phones are adding
power draining features such as large color
screens, cameras, other radios (GPS, WiFi,
Bluetooth). A contrary trend has been the
consumers quick adoption of slim phones, which
demands a thin battery with limited mA-hour
capacity.
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Drivers for improved performance in FEM
Components Example 2
Service providers are demanding tighter
specifications such as noise sensitivity and
reduction of spurious emissions both
specifications that affect the phones ability to
meet and improve quality of service (QoS). A
contrary trend has been the adoption by handset
manufacturers of CMOS over SiGe. But, a CMOS
front end is not as clean as SiGe
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Drivers for improved performance in FEM
Components Example 3
For many front end components, smaller size and
better performance (e.g. isolation specs) can be
mutually exclusive A counter trend has been
the adoption of internal antennas, requiring both
better performance AND smaller size to
accommodate poorer antenna performance and
internal size
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Drivers for improved performance in FEM
Components Example 4
The creation of EGSM in Europe, E-850 and the
G-block spectrum in PCS, has started a trend of
taking bandwidth away from the guard band between
Tx and Rx spectrum and giving this spectrum to
the user This means that the duplexer will
need a wider bandwidth, and increased Q to meet
the need for steeper skirts
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Drivers for improved performance in FEM
Components Example 5
The addition of more parallel radios to cover
more frequency bands forces combining at the
antenna Switches, diplexers etc are needed
to allow for combining at the antenna but cause
loss pushing the insertion loss specs on
duplexers
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GSM (today)
RFIC QB PA (Low and high channel) SP6T switch
(all T/R functionality) 4 x Rx filters (SEDE)
But, GSM phones are moving to 3rd Generation UMTS
and need wide-band CDMA technologies for the
Front End
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UMTS Gen.2 (US Band 1)
RFIC QB PA (Low and high channel) Antenna to SP9T
switch (hard, due to linearity
concerns) Separate GPS receiver antenna
B1
B2
By-Band FEM
B5
GPS Antenna
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By-Band FEM
UMTS By-Band FEM4X7 mm2
CDMA By-Band FEM5X8 mm2

• Advantages
• Small size
• Low Current draw
• Optimized PA/Duplexer
• Time to Market
• Keep phone, but change FEM for different regions

• Band 1 1920-1980 MHz 2110-2170 MHz Europe, Asia
  Pacific
• Band 2 1850-1910 MHz 1930-1990 MHz US (UMTS
  CDMA)
• Band 3 1710-1785 MHz 1805-1880 MHz Europe, Asia
  Pacific
• Band 9 1750-1785 MHz 1845-1880 MHz Japan
• Band 4 1710-1755 MHz 2110-2155 MHz US (AWS
  band) Band 10 1710-1770 MHz 2110-2170
  MHz Latin America
• Band 5 824-849 MHz 869-894 MHz US (UMTS CDMA)
• Band 6 830-840 MHz 875-885 MHz Japan
• Band 7 2500-2570MHz 2620-2690 MHz
  LTE
• Band 8 880-915 MHz 925-960 MHz Europe, Asia
  Pacific

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Why a By-Technology FEM?

• Improved duplexer performance better insertion
  loss, better isolation, better linearity, and,
  smaller size (while meeting ASP erosion curves)

Example of FBAR Duplexer to Multiplexer Migration
3.8 X 3.8 mm2 duplexer
4 X 7 mm2 Quintplexer
Uses the off-frequency, High-Q property of FBAR
to minimize loading
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Reasons for Quintplexer Migration

• Beyond Improved duplexer performance better
  insertion loss, better isolation, better
  linearity, and, smaller size (while meeting ASP
  erosion curves)
• Eliminates diplexer (0.2dB loss) GPS Switch
  (0.5 dB loss) longer traces and matching SMTs
  (0.3 dB)
• Get better broad band signal rejection
• Smaller size allows more functionality elsewhere
• Allows for Simultaneous GPS due to high
  rejection of the transmit energy from either PCS
  or Cell band into GPS band
• For multi-Band W-EDGE phones, can save switch
  ports, simplifying switching

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UMTS Multiplexers

• Features
• Combines duplexers for two bands with single
  antenna port.
• Improves talk time by
• Lower front end losses from elimination of switch
  or diplexer
• Uses low loss, steep walled FBAR filter
  technology
• Better broad band rejection due to presence of
  extra filtering
• Fewer switch throws required, so less linearity
  burden on the switch
• Simplifies phone design and reduces BOM.

antenna
Band A Tx
Band A Rx
Band B Tx
Band B Rx

• Products in Development
• Band 1 8 1920-1980 MHz 2110-2170 MHz Europe,
  Asia Pacific
• 880 915 MHz 925-960 MHz
• Band 2 5 1850-1910 MHz 1930-1990 MHz US
• 824 849 MHz 869-894 MHz

Product of the yearElectronic products (narrow
cdma version)
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Non-Silicon FEM Technologies
Hi Q, FBAR freq. source
Highly Linear Multi-Throw Switch (SP8T)
Multi-Band PA
B1
B2
By-Band FEM
B5
GPS
By-Technology FEM
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Using Temperature Stable, High-Q FBAR resonators
to enable lower power CMOS Transceivers and other
ASICs
First Lab bench Test of Temperature Stable FBAR
resonator Ultimate packaged resonator size ? 0.2
mm2 by 0.2 mm tall
Excellent Phase Noise -104 dBc _at_ 1 KHz
Offset Integrated Jitter ? 95 fs (10 KHz to 80
MHz) 30X better than Si-MEMS

• Very small, packaged resonators (uses silicon
  WLP )
• Temperature stability quartz
• VCO operates at fundamental (e.g. 1, 1.5, 2.4,
  3.0 GHz)
• Lower Power ? replace PLLs, low freq. oscillator,
  low Q VCO, while simultaneously achieving
  excellent jitter with less power in core
  oscillator

/- 25 ppm over 100C Temperature Stability
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Conclusion
Specialized Technologies (GaAs, FBAR, etc)
continue to meet the additional demands placed on
the Front End components of mobile phones
something that CMOS cannot do now, and, will not
be able to do for a long time!
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