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June 2-3 . Detroit , USA
Automotive Connector Simulation vs Measurement
A Case Study
Sungjong Yoo, Ph.D, Electrical Design Engineer, Molex Inc.
David Dunham, Director Electrical Engineering, Molex Inc.
June 2-3 . Detroit , USA
Overview
�What this presentation will cover
– Typical Automotive Cable & Connector Assembly
– HFSS Simulation Setup
– Correlated results of a Typical Automotive Connector
– Simulation Conclusions
– Summary• What data speeds would this simulation apply to.
• Who should be using this analytical/empirical approach.
Thursday, May 28, 2015 2015 Automotive Simulation World Congress 2
June 2-3 . Detroit , USA
Automotive Cable & Connector Assembly
• Typical Structure of automotive Cable & Connector Assembly
– Twisted cable is connected to connector plug.
– R/A header pins connected to PCB.
– PCB designed for matched channel impedance.
Thursday, May 28, 2015 2015 Automotive Simulation World Congress 3
Twisted cable
Plug
Crimp
Terminal
Pin
Header
PCB
June 2-3 . Detroit , USA
HFSS Simulation for Automotive
Cable/Connector Assembly
Thursday, May 28, 2015
• Insertion loss (IL) is used to verify connector loss
budget.
• Return Loss (RL) is used to verify worst case reflection
as a function of frequency
• Sdc mode conversion quadrant defines possible EMI
issues, as a function of frequency.
• TDR defines worst case impedance changes in the
structure, (directly related to RL).
2015 Automotive Simulation World Congress 4
June 2-3 . Detroit , USA
Typical mated connector model with integrated
PCB launch.
16.25mm
7.5mm
14.5mm
Thursday, May 28, 2015 2015 Automotive Simulation World Congress 5
Typical Automotive terminal
June 2-3 . Detroit , USA
Measurement vs Model Setup
Thursday, May 28, 2015 2015 Automotive Simulation World Congress 6
Measured Setup Simulation Setup
June 2-3 . Detroit , USA
HFSS Connector Setup/Simulation Results
Frequency Domain
Thursday, May 28, 2015 2015 Automotive Simulation World Congress 7
June 2-3 . Detroit , USA
HFSS simulation setup
• Typical setup
– Solution Frequency: typically 20GHz
– Max delta s: 0.01, to full convergence
– First order direct solver
– Interpolating sweep from 10 MHz to 20 GHz
– HFSS TDR – Rise time is based on highest sweep freq.
– 50 ohm wave ports used
– Boundary condition – air box
Thursday, May 28, 2015 2015 Automotive Simulation World Congress 8
June 2-3 . Detroit , USA
Insertion Loss: Simulation vs. Measurement
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Insertion loss plots show reasonable correlation.
Red: Measurement
Brown: Simulation
June 2-3 . Detroit , USA
Return Loss: Simulation vs. Measurement
Thursday, May 28, 2015 2015 Automotive Simulation World Congress 10
Return loss plots show good correlation up to 1 GHz
Red: Measurement
Brown: Simulation
June 2-3 . Detroit , USA
Mode Conversion (Sdc11)
Simulation vs. Measurement
Thursday, May 28, 2015 2015 Automotive Simulation World Congress 11
Simulation and measurement plots have reasonable correlation
from 10 MHz to 1 GHz.
Dotted Red: 1Gbps MDI Limit
Red: Measurement
Brown: Simulation
June 2-3 . Detroit , USA
Mode Conversion (Sdc12)
Simulation vs. Measurement
Thursday, May 28, 2015 2015 Automotive Simulation World Congress 12
Simulation and measurement results have 20 dB difference at 10 MHz,
gap reduces as frequency gets higher .
Dotted Red: 1Gbps MDI Limit
Red: Measurement
Brown: Simulation
June 2-3 . Detroit , USA
Mode Conversion (Sdc22)
Simulation vs. Measurement
Thursday, May 28, 2015 2015 Automotive Simulation World Congress 13
Simulation and measurement have 15 dB difference at 10
MHz, the gap is reduced as frequency is getting higher.
Dotted Red: 1Gbps MDI Limit
Red: Measurement
Brown: Simulation
June 2-3 . Detroit , USA
Mode Conversion (Sdc21)
Simulation vs. Measurement
Thursday, May 28, 2015 2015 Automotive Simulation World Congress 14
Simulation and measurement have 20 dB difference at 10 MHz, the gap is
reduced as frequency is getting higher.
Dotted Red: 1Gbps MDI Limit
Red: Measurement
Brown: Simulation
June 2-3 . Detroit , USA
HFSS Connector Setup/Simulation Results
Time Domain
Thursday, May 28, 2015 2015 Automotive Simulation World Congress 15
June 2-3 . Detroit , USA
TDR (25 ps)
Simulation vs. Measurement
Thursday, May 28, 2015 2015 Automotive Simulation World Congress 16
1. Capacitance between
antipad and via.
2. Inductance around the
connection pin in the
waterfall region.
3. Capacitance between
two crimps of terminals.
1
2
3
TDR with 25 ps filter is used to observe the impedance variation
of geometry.
June 2-3 . Detroit , USA
Conclusions
• HFSS simulation results of high speed connector
shows good correlation in TDR, return loss, and
insertion loss.
• VNA mode conversion noise floor causes some
mismatch of mode conversion at frequencies below
10 MHz.
Thursday, May 28, 2015 2015 Automotive Simulation World Congress 17
June 2-3 . Detroit , USA
Summary
• This simulation can apply to data rates above 1GB/s with the following notations:
– Mode conversion correlation methodology needs further investigation
– Adding twisted wire for channel simulations will need further evaluation as to the correct modeling methodology
• This methodology is good to define:
– Connector design before production tooling
– PCB tuning and effects on the connector design
Thursday, May 28, 2015 2015 Automotive Simulation World Congress 18
June 2-3 . Detroit , USA
Thank You!
Thursday, May 28, 2015 2015 Automotive Simulation World Congress 19