JANUARY 28-31, 2013
SANTA CLARA CONVENTION CENTER
Effects of Temperature and Relative Humidity
in Transmission Systems Using Differential
Signaling
Authors
•
•
•
•
•
•
•
•
•
•
Aldo Morales
Email: awm2@psu.edu
Sedig Agili
Email: ssa10@psu.edu
Mike Resso
Email: mike_resso@agilent.com
Jeff Clark
Email: jmc5444@psu.edu
Chris Kocuba
Email: Chris.Kocuba@samtec.com
Presentation Outline
•
•
•
•
•
•
•
Introduction
Previous Research
Experimental Set Up and Procedure
Experimental Results Analysis
Summary
Acknowledgements
References
Introduction
• In this paper, we explore the of humidity and
temperature effects on PCB boards with differential
signaling.
• Of particular interest is S-parameters mode
conversion due to the asymmetry induced by the
moisture absorption in the differential lines.
• Note hat asymmetry can also convert some of the
differential signals into common signals. This
asymmetry can also lead to signal skew that affects
bandwidth, degrades rise time as well as increases
electro-magnetic interference
Previous Research
• S21 measurements, microstrip using
FR4 without solder mask
• S21 measurements, microstrip using
Rogers 4350
FR4 0.0300 inch thick microstrip line, dry and 7 days at 55 C 95% RH
Rogers 4350 0.0300 inch thick microstrip line, dry and 7 days at 55 C 95% RH
0
0hr
24hrs
-1
72hrs
120hrs
168hrs
-2
0
0hr
24hrs
72hrs
120hrs
168hrs
-2
-4
S21 (dB)
-8
S
21
(dB)
-6
-3
-4
-10
-5
-12
-6
-14
-16
0
5
10
15
Frequency (GHz)
20
25
-7
0
5
10
15
Frequency (GHz)
20
DesignCon 2010, “Evaluation of Relative Humidity and Temperature Effects
on Scattering Parameters in Transmission Systems”
25
Previous Research
• S21 magnitude measurements and curve fitting line.
– S21 magnitude vs. time as 1GHz S21 magnitude vs. time as 20GHz
DesignCon 2010
6
Previous Research
•Soaked samples were exposed to 1 week of 30 ˚C and 60 % RH, S21 of GMS
DesignCon 2012, “Temperature and Moisture Dependence of PCB and
Package Traces and the Impact on Signal Performance,” Miller et. al.
Previous Research
DesignCon 2012, “Temperature and Moisture Dependence of PCB and
Package Traces and the Impact on Signal Performance,” Miller et. al.
Experimental Set Up and Procedures
• Test devices:
– Samtec golden standard
– Milled
– XAUI
9
Experimental Set Up
• Temperature & humidity
chamber
– (-34)°C to 190°C
– 10% to 98% RH
•
Performance Network Analyzer
– Agilent E8364B (0 to 50 GHz)
– SOLT calibration
– Physical Layer Test System
10
Experimental Set Up
• Temperature chamber for
baking the DUTs
•
Mettler AE 100 lab scale
– 100g capacity;
– 0.0001g readability
11
Experimental
Procedure
Bake all DUTs at 80 oC for 4 days
SOLT calibration
S-parameter measurements of DUTs
(dry state)
SOLT
Freq start: 50 MHz
Freq end: 26 GHz
IF bandwidth: 100 Hz
801 points
Microstrip line test board
Freq start: 50 MHz
Freq end: 26 GHz
IF bandwidth: 100 Hz
801 points
1 measurement each time
Place DUTs in the environmental chamber kept
at 55 oC and 95% RH
S-parameters measurements of DUTs
No
Every 12 hours for 7 days
complete?
Yes
Results analysis and S-parameter simulation
12
Experimental Results Analysis
13
Experimental Results Analysis
14
Experimental Results Analysis
15
Experimental Results Analysis
16
Experimental Results Analysis
gldstd S12-parameters single ended
gldstd S11-parameters single ended
0
0
0 Hrs
118 Hrs
7 days
-5
0 Hrs
118 Hrs
7 days
-10
-10
-20
-15
-30
S12
S11
-20
-25
-40
-30
-50
-35
-40
-60
-45
-50
-70
0
5
10
15
Frequency GHz
20
25
0
5
10
15
Frequency GHz
17
20
25
Experimental Results Analysis
18
Experimental Results Analysis
19
Experimental Results Analysis
20
Experimental Results Analysis
XAUI far end crosstalk at 0 Hrs and 7 days
XAUI near end crosstalk at 0 Hrs and 7 days
0
0
NEXT 0 Hrs
NEXT 7 days
-10
FEXT 0 Hrs
FEXT 7 days
-10
-20
-30
-30
-40
-40
dB
dB
-20
-50
-50
-60
-60
-70
-70
-80
-80
-90
0
1
2
3
Frequency GHz
4
5
6
-90
0
1
2
3
Frequency GHz
21
4
5
6
Conclusions and Future Work
• Differential parameters, for all board analyzed, show consistent
degradation in performance while mode conversion shows
upswing in some regions of the boards’ range of operation
• NEXT and FEXT are also affected in some regions of operation but
the change seem to be less than mode conversion and in
differential S-parameters
• More research in how moisture absorption and temperature
change the balance lines (for example layer placement)
• Influence of the board weave.
22
References
[1] Paul Hamilton, Gary Brist, Guy Barnes, Jr. & Jason Schrader, Humidity-dependent Loss in PCB Substrates in
http://members.ipc.org/IPCLogin/IPCMembers/IPC/Route/0507/tech.pdf
[2] J. Miller, Y. Li, K. Hinckley, G. Blando, B. Guenin, I. Novak, A. Dengi, A. Rebelo and S. McMorrow, “ Temperature and Moisture
Dependence of PCB and Package Traces and the Impact on Signal Performance,” Proceedings of Designcon 12, Santa Clara, CA,
2012.
[3] G. Sheets and J. D’Ambrosia “Evaluating Environmental Impact on Channel Performance,” CommDesign May 2004,
http://www.commsdesign.com/design_corner/showArticle.jhtml?articleID=20300581.
[4] S. Agili, A. Morales, J. Li and M. Resso, “Modeling Relative Humidity and Temperature Effects on Scattering Parameters in
Transmission Lines, “ IEEE Transactions on Components, Packaging, and Manufacturing Technology, November-December 2012.
[5] D.I. Amey, S.J. Horowitz, R.L. Keusseyan, “High Frequency Electrical Characterization of Electronic Packaging Materials:
Environmental and Process Considerations,”. Proceedings of the 4th International Symposium Advanced Packaging Materials,
1998.
[6] J-M Heinola, K-P. Lätti, P. Silventoinen, J-P. Ström, and M. Kettunen, “A Method to Evaluate Effects of Moisture Absorption on
Dielectric Constant and Dissipation Factor of Printed Circuit Board Materials,” Proceedings of the 9th International Symposium
on Advanced Packaging Materials: Processes, Properties and Interfaces, 2004.
[7] H. Fremont, et al, “Measurements and FE-Simulations of Moisture Distribution in FR4-based Printed Circuit Boards”, 7th Int.
Conf. On Thermal, Mechanical and Multiphysics Simulation and Experiments in Micro Electronics and Micro-Systems, EuroSimE
2006.
23
References
[8] J. Li, M. Minns, A. Morales , S. Agili, M. Resso, “Evaluation of Relative Humidity and Temperature Effects on
Scattering Parameters in Transmission Systems,” Proceedings of Desigcon10, February 2010, Santa Clara, CA.
[9] E. Bogatin, Signal integrity Simplified, Prentice Hall, 2003.
[10] J. Nadolny, S. Sercu, “Characterization And Impact Of Skew On Differential Connector Systems” Proceedings of 18th
International Zurich Symposium on Electromagnetic Compatibility, Zurich, Switzerland, February 20-22, 2001.
[11] J. Nadolny, J. Ferry, and C. Arroyo, “Mode Conversion and EMI Performance of Shielded Cable Assemblies for 10
Gbps Data Transmission,” Proceedings of Desigcon08, February 2008, Santa Clara, CA.
[12] C. Di Minico and P. Kish, “Development of Equal Level Far-End Crosstalk (ELFEXT) and Return Loss Specifications for
Gigabit Ethernet Operation On Category 5 Copper Cabling,” at
www.ieee802.org/3/an/public/material/diminico_IWCS.PDF last accessed 12/01/2012.
24
Acknowledgements
This research was possible thanks to the following Sponsors:
25
Thank you for your attention
I welcome your questions..
QUESTIONS?