Steckverbinder in Hochgeschwindigkeitssystemen

Steckverbinder in Hochgeschwindigkeitssystemen

Steckverbinder in
Hochgeschwindigkeitssystemen
Thomas Gneiting, AdMOS GmbH
thomas.gneiting@admos.de
Company Information
• AdMOS was founded in 1997 by Dr.
Thomas Gneiting.
• AdMOS is focused on:
– Software development of tools for
model parameter extraction of CMOS
and other devices.
– Service for modeling and simulation of
complex devices and systems.
– Engineering service for design and test
AdMOS GmbH
of RF and high speed components.
Advanced Modeling Solutions
• Actually, we employ 5 highly qualified
In den Gernaeckern 8
engineers for our modeling service and
D-72636 Frickenhausen/Germany
software development activities.
Phone: +49 (7025) 911698-0
• Due to our ongoing expansion, we moved
Fax:
+49 (7025) 911698-99
to a new office building in December
2007.
email: info@admos.de
http://www.admos.de
Table of Content
• Typical examples for high speed interconnect systems
–
–
Communication System
Industrial Computer System
• Influence of connectors to the performance of high
speed systems
• Demonstration of a high performance connector
• Connector to PCB interface as a limiting factor
• Future requirements
Communication System
Daughter card with
Processor, IO, etc.
Male Connector
Female
System (e.g. Router, Switch)
Connector with back plane
Principle Architecture Communication System
Signal paths with a serial point
to point connection on
differential lines up to 10Gbit/s
NRZ code.
High Speed Multi
Pin Connector
Transmitter/
Receiver
Backplane
System
Host Board
Signal via with
differential traces
Transmitter/
Receiver
Daughtercard
Daughtercard
Industrial Computer System
S-ATA
BPL
3
S-ATA
USB
GBE
USB
GbE
5
4
2
1
PCI Express:
Prozessor  Add-In
2
PCI Express:
Prozessor  BPL Silicon
3
Serial ATA:
Prozessor  Disk via BPL
4
Gigabit Ethernet:
Prozessor  anderes
System via BPL
5
USB 2.0:
Prozessor  Peripherie
via BPL
BPL Silicon
Connector
1
Processor
board
Transmitter/
Receiver
Add in cards
Table of Content
• Typical examples for high speed interconnect systems
• Influence of connectors to the performance of high
speed systems
–
–
–
Impedance and reflection behavior
Crosstalk
Eye diagrams
• Demonstration of a high performance connector
• Connector to PCB interface as a limiting factor
• Future requirements
Key components for SI analysis in this chapter
PCB Striplines
Signal path
Backplane
High Speed Connector
to Board Transition
High Speed Connector
System
Host Board
Transmitter/Receiver
Transmitter
out +
8B10B 6.25 Gbit/s
out -
Daughtercard
Daughtercard
Signal via with
Vias
(here for differential signal lines)
Modeling the Passive Signal Path
Port
P2
Num=2
Port
P1
Num=1
VAR
Design_Settings
Trace_length=500
Trace_width=0.15*factor_width
Trace_spacing=0.4
Trace_thickness=0.035
Pre_break_height=0.24
er=FR4_er
tan_d=FR4_tan_d
cbi_Backplane=cbp_PF_FR4_top
cbi_Daughter=cdt_PF_FR4_top
Port
P3
Num=3
g
h
Daughter
card
Differential traces:
ADS PCB multiline
models
Board
Contact
Model
Port
P4
Num=4
Connector
Model
g
h
Daughter
card
h
h
g-h
g-h
g
spar_lb_daughter
X2
er_dt2=er
B_dt2=2*Pre_break_height
T_dt2=Trace_thickness
tand_dt2=tan_d
W_dt2=Trace_width
S_dt2=Trace_spacing
len_dt2=50
g
e-f
c-d
a-b
a-b c-d e-f
g-h
spar_lb_daughter
X3
er_dt2=er
B_dt2=2*Pre_break_height
T_dt2=Trace_thickness
tand_dt2=tan_d
W_dt2=Trace_width
S_dt2=Trace_spacing
len_dt2=50
Board
Contact
Model
Integration of Touchstone Spar
files coming from CST
Microwave Studio
Models are hierarchical and fully parameterized to allow
simulation of different configurations (trace lengths, board
material) or statistical analyses.
c-d
a-b
g-h
a-b c-d e-f
spar_stecker_alle
Stecker2
spar_stecker_alle
Stecker1
Connector plus board
contact (Micro Vias or not):
e-f
g
h
g
Backplane
spar_lb_backplane
Backplane
er_bp2=er
T_bp2=Trace_thickness
B_bp2=2*Pre_break_height
tand_bp2=tan_d
len_bp2=Trace_length
W_bp2=Trace_width
S_bp2=Trace_spacing
h
Characteristic Impedance Time Domain
Var
Eqn
TRANSIENT
DUT
8
Ue7
Ue8
9
Ue9
7
10
Ue10
11
Ue11
ERNI ERmet ZD connector
2nd connector
115
12
model_DUT
X1
sim_index=3
VAR
VAR
SRC_Vhigh=1
SRC_Rise=85e-12
SRC_Period=80e-9
Backplane
110
Ue12
105
100
impededance Ohm
Ue1
VtPulse
SRC4
R
TLIN
Vlow=0 V
R20
TL2
Vhigh=SRC_Vhigh t
R=50 Ohm
Z=50.0 Ohm
Edge=cosine
E=60
Rise=SRC_Rise
F=1 GHz
Fall=SRC_Rise
Width=SRC_Period/2-SRC_Rise
Period=SRC_Period
Ue2
VtPulse
R
SRC5
TLIN
R21
1
Vlow=0 V
TL4
t
R=50 Ohm
Vhigh=-SRC_Vhigh
Z=50.0 Ohm
2
Edge=cosine
E=60
Rise=SRC_Rise
F=1 GHz
Ue3 3
Fall=SRC_Rise
Ue4
4
Width=SRC_Period/2-SRC_Rise
Period=SRC_Period
Ue5
5
VtPulse
6
R
SRC6
TLIN
R24
Vlow=0 V
TL5
t
R=50
Ohm
Vhigh=SRC_Vhigh
Z=50.0 Ohm
Edge=cosine
E=60
Rise=SRC_Rise
F=1 GHz
Fall=SRC_Rise
Width=SRC_Period/2-SRC_Rise
Period=SRC_Period
Ue6
VtPulse
R
SRC7
TLIN
R25
Vlow=0 V
TL6
t
R=50
Ohm
Vhigh=-SRC_Vhigh
Z=50.0 Ohm
Edge=cosine
E=60
Rise=SRC_Rise
F=1 GHz
Fall=SRC_Rise
Width=SRC_Period/2-SRC_Rise
Period=SRC_Period
95
90
85
80
75
70
65
60
0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 2.1 2.3 2.5 2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3 4.5 4.7 4.9 5.1 5.3 5.5 5.7 5.9
time, nsec
Plated through hole vias for the
ERNI ERmet ZD connector (press-in technique)
Crosstalk Time Domain
Ue1
VtPulse
SRC4
R
TLIN
Vlow=0 V
R20
TL2
Vhigh=SRC_Vhigh t
R=50 Ohm
Z=50.0 Ohm
Edge=cosine
E=60
Rise=SRC_Rise
F=1 GHz
Fall=SRC_Rise
Width=SRC_Period/2-SRC_Rise
Period=SRC_Period
Ue2
VtPulse
R
SRC5
TLIN
R21
1
Vlow=0 V
TL4
t
R=50 Ohm
Vhigh=-SRC_Vhigh
Z=50.0 Ohm
2
Edge=cosine
E=60
Rise=SRC_Rise
F=1 GHz
Ue3 3
Fall=SRC_Rise
Ue4
4
Width=SRC_Period/2-SRC_Rise
Period=SRC_Period
Ue5
5
VtPulse
6
R
SRC6
TLIN
R24
Vlow=0 V
TL5
t
R=50
Ohm
Vhigh=SRC_Vhigh
Z=50.0 Ohm
Edge=cosine
E=60
Rise=SRC_Rise
F=1 GHz
Fall=SRC_Rise
Width=SRC_Period/2-SRC_Rise
Period=SRC_Period
Ue6
VtPulse
R
SRC7
TLIN
R25
Vlow=0 V
TL6
t
R=50
Ohm
Vhigh=-SRC_Vhigh
Z=50.0 Ohm
Edge=cosine
E=60
Rise=SRC_Rise
F=1 GHz
Fall=SRC_Rise
Width=SRC_Period/2-SRC_Rise
Period=SRC_Period
Maximum NEXT in the
via sections of the
connector !
TRANSIENT
DUT
8
Ue7
Ue8
9
Ue9
7
10
Ue10
11
Ue11
Var
Eqn
VAR
VAR
SRC_Vhigh=1
SRC_Rise=85e-12
SRC_Period=80e-9
Impedance
12
model_DUT
X1
sim_index=3
Ue12
The connector itself
generates very low
crosstalk
S-Parameter of Differential Traces
DUT
in
out
1
7
2
8
3
9
4
10
5
11
6
12
Transmission
0
model_DUT
X1
PCB
-5
dB(S(5,6))
Var
Eqn
S-PARAMETERS
-10
Reflection
0
-15
0.0
-5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
freq, GHz
-10
dB(S(5,5))
Differential
S-parameters
in Odd mode.
0.5
-15
-20
-25
-30
-35
-40
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
freq, GHz
4.0
4.5
5.0
5.5
6.0
5.5
6.0
Eye Diagrams (Measured and Simulated)
S M A connectors
DUT
B ackplane
ee
B it P attern G enerator
O scilloscope
A gilent 86100
A
Datastream: 10Gbit/s NRZ
Summary: Connector Influence
The following list shows, which component mainly
influences performance degradations in high speed
systems:
• Signal loss (|S21|):
is mostly dominated by the losses in the PCB
• Xtalk:
can be very high in the connector to PCB interface
• Reflections:
can be very high in the connector to PCB interface
interface
• Skew: in both, the connector and the PCB interface
Table of Content
• Typical examples for high speed interconnect systems
• Influence of connectors to the performance of high
speed systems
• Demonstration of a high performance connector
–
–
ERNI ERmet ZD and ERmet 0XT
Critical issues in connector designs
• Connector to PCB interface as a limiting factor
• Future requirements
Example Connector (1): ERNI ERmet ZD
Differential
traces
4 differential
signal pairs
per
connector
wafer
Shielding
components
Shielding in the
male connector
Pressfit pins for
signals and ground
shields
Example Connector (2): ERNI ERmet 0XT
Differential
traces
4 differential
signal pairs
per
connector
wafer
micro-vias for the
signal
interconnections
Shielding
components
Ground
connections
using
Pin in Paste
technology
Construction ERNI ERmet ZD
Federleiste
(Female)
Abdeckung
Kontaktaufnahme
Federkontakte
Deckel
Schirmblech
Schirmblech
Messerkontakte
Kontaktaufnahme
Messerleiste
(Male)
Critical Issues in Connector Design
Contact Design and
overlay between male
and female conductor
Shielding
Pressfit Pins
Skew between the 2 conductors
of a differential pair
Advances in Contact Design
D-Sub
DIN
ERmet
SMC
ERmet ZD
Minimized discontinuities by minimized contact structures
Microspeed
EM Analysis to Support Connector Design
Table of Content
• Typical examples for high speed interconnect systems
• Influence of connectors to the performance of high
speed systems
• Demonstration of a high performance connector
• Connector to PCB interface as a limiting factor
–
–
Demonstrator
Comparison between Pressfit Technology, Microvias and
Backdrilling
• Future requirements
Case Study: ERNI ERmet 0XT
This case study takes into account the connector to PCB interface of the ERNI
ERmet 0XT connector which can be used for data rates of at least 10GBit/s.
The simulations are performed in a fully 3-D EM simulator (CST Microwave
Studio).
Different kind of interfaces
Setup 1
Setup 2
Setup 3
Connector pad
Via type
SMT
Microvia
SMT
Through hole
Via diameter
Signal layer
0.35
Top
Pressfit
Throughole with
backdrill
0.5
Top
Zoomed cross
section
0.3
Bottom
Different kind of interfaces
Setup 1
Setup 2
Setup 3
Connector pad
Via type
SMT
Microvia
SMT
Through hole
Via diameter
Short
Signal
layer
0.35
Top
Pressfit
Throughole with
backdrill
0.5
Top
Zoomed cross
section
pressfit pin
Line in PCB
Backdrilled
through via
0.3
Bottom
Different kind of interfaces
Setup 1
Setup 2
Setup 3
Connector pad
Via type
SMT
Microvia
SMT
Through hole
Via diameter
Signal layer
0.35
Top
Pressfit
Throughole with
backdrill
0.5
Top
Zoomed cross
section
SMD Pad
Microvia
Line in PCB
0.3
Bottom
Different kind of interfaces
Setup 1
Setup 2
Setup 3
Zoomed cross
section
Connector pad
Via type
SMT
Microvia
Via diameter
Signal layer
0.35
Top
Pressfit
Throughole with
Through via
backdrill
0.5
Top
SMT
Through hole
0.3
SMD pad
Bottom
Line in PCB
Performance: Impedance + Crosstalk
Impedance
NEXT
SMT pad, microvia
SMT pad, through hole via
Pressfit, backdrill
SMT pad, microvia
SMT pad, through hole via
Pressfit, backdrill
FEXT
Signal:
Step with a rise time of
50ps (20 to 80%)
SMT pad, microvia
SMT pad, through hole via
Pressfit, backdrill
Table of Content
• Typical examples for high speed interconnect systems
• Influence of connectors to the performance of high
speed systems
• Demonstration of a high performance connector
• Connector to PCB interface as a limiting factor
–
–
Demonstrator
Comparison between Pressfit Technology, Microvias and
Backdrilling
• Future requirements
Future Requirements High Speed Connectors
• Minimize reflections through miniaturisation and optimisation of
the mating zone
• Keep crosstalk low with improved shielding or clever arrangement
of signals
• Improve connector to PCB interface by the usage of
– smaller pressfit zones
– BGA like balls to solder on SMT pads ?
• Improve skew behavior
Connectors should be ready for the 40GBit/s challenge as outlined in the
BMBF Verbundprojekt Giganoboard:
„... Deshalb stellt die Entwicklung von hochintegrierten, komplexen
Leiterplatten für die elektrische Datenübertragung bis 40 GBit/s ..... eine
Schlüsseltechnologie dar. .... „