Multi-Standard Mobile Broadcast Receiver LNA with Integrated Selectivity and Novel Wideband Impedance Matching Technique* - PowerPoint PPT Presentation

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Multi-Standard Mobile Broadcast Receiver LNA with Integrated Selectivity and Novel Wideband Impedance Matching Technique*

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Title: Multi-Standard Mobile Broadcast Receiver LNA with Integrated Selectivity and Novel Wideband Impedance Matching Technique*


1
Multi-Standard Mobile Broadcast Receiver LNA with
Integrated Selectivity and Novel Wideband
Impedance Matching Technique
  • Tae Wook Kim, Ph. D
  • Yonsei University
  • Published in IEEE JSSC Mar. 2009

2
Outline
  • Overview of Mobile TV standards
  • Design challenges/Receiver Overview
  • LNA Design
  • Integrated Notch Filter
  • Partial Feedback
  • Measurement Result
  • Conclusion

3
Mobile TV Standards
  • US MediaFLO USA 696MHz-746MHz
  • Europe DVB-H 470MHz-750MHz, MediaFLO (L-Band)
  • Korea T-DMB (VHF)
  • Japan MediaFLO, ISDB-T 470MHz-770MHz
  • Standards defined for portable applications
  • Mobile phone, Personal media player
  • Low power consumption, small form factor low
    cost
  • Receivers ability to concurrently operate with a
    GSM/DCS/WLAN Transmitter is a plus.

4
Design Challenges - I
  • Jammers in the UHF band are analog TV signals and
    DVB-T/H wideband signals
  • Adjacent channel jammers can cause IM2/IM3 ? C/N
    degradation
  • Large adjacent channel jammer can de-sense the
    receiver ? C/N degradation
  • Receiver needs to have high linearity in order
    achieve VBERlt2e-4 for all these jammer cases

5
Design Challenges - II
  • Concurrent Receiver operation with a GSM/DCS/WLAN
    TX is a desirable feature
  • GSM900 TX can de-sense or generate IM2 in the
    direct conversion receiver
  • DCS/WLAN TX can mix with harmonics of LO and
    down-convert to baseband frequencies ?
    significant degradation in C/N
  • Receiver needs to have front end selectivity to
    attenuate these TX jammers

6
Out-of-band interference scenario for DVB-H
7
Receiver Overview
8
RF Front End Wideband LNA
  • Differential LNA topology
  • Common mode rejection
  • Package parasitic have minimal impact on the
    amplifier and elliptic filter
  • Elliptic Filter
  • Elliptic filters are tuned to 1.8GHz ? high
    impedance at TX jammer frequency
  • TX jammers are attenuated gt 78dB
  • LNA gain control range 50dB

9
Integrated Notch Filter
10
Integrated Notch Filter
  • Requirements for high rejection
  • High Q inductor
  • Low k between inductor
  • Q(1-k) Q
  • 3. Symmetry between inductors (symmetric
    interference can be cancelled by differential
    operation)

Low k
Symmetry
Low k
Low impedance _at_ signal High impedance _at_ jammer
High impedance _at_ signal Low Impedance _at_ jammer
11
Coupling between Coils
Substrate coupling
Magnetic coupling, k
12
Input Matching
Common gate It can provide wideband input
matching and high output impedance but it NF is
as high as 3 dB which is not acceptable
Passive, Active Feedback Feedback topology can
provide wideband input matching and good NF but
it has low output impedance and it cannot have
notch filter inside
13
Instability
Fig. 5
  • It is risky to have notch filter inside the loop
    in the Feedback Network
  • It may cause instability.

14
Partial feedback amplifier
(W1 is width of M1)
output
In the partial feedback amplifier there are two
loops. One is closed loop (M1 and M2) and the
other is open loop. The closed provide Wideband
input matching. And open loop (M1 and M3)
provide signal amplification. Then it can
provide wideband input matching also high output
impedance. Also, when we place notch filter at
the open loop. So, there is no stability issue.
input
  • Feedback loop
  • provide wideband input/noise
  • matching
  • Open loop
  • Provide high output impedance
  • Can have notch filter inside

15
LNA Schematic Diagram
Partial Feedback
16
Measurement Result Gain vs. Freq.
17
S11 Measurement Wideband LNA
18
Gain vs. Freq. (in band response)
19
LNA Out-of-band rejection
20
DVB-H NF
21
Die photo
LNA
PLL
22
Performance Comparison
1 T.H Lee, TMTT 2002 2 A. Bevilacqua ISSCC
2007
23
Conclusion
  • DVB-H LNA is Designed and Measured
  • Concurrent Operation with DCS, WLNA
  • Integrated Notch Filter with 78dB rejection
  • Partial Feedback for wideband matching with notch
    filter
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