MICRO SAS-3 VERTICAL SMT RECEPTACLE
BOARD LAYOUT AND ROUTING GUIDELINES
TABLE OF CONTENTS
1.0
2.0
SCOPE
PC BOARD REQUIREMENTS
2.1
MATERIAL THICKNESS
2.2
LAYOUT
HIGH SPEED ROUTING
3.1
TRACE TO PAD ATTACHMENT
3.2
GROUD VIA PLACEMENT
3.3
IMPEDANCE MATCHING AT TRACE AND FOOTPRINT/PAD
3.4
HIGH SPEED REFERENCE PLANE ANTI-PAD
3.5
SKEW COMPENSATION FOR DIFFERENTIAL ROUTING
3.6
TRACE COMPARISON
3.0
REVISION:
ECR/ECN INFORMATION: TITLE:
EC No:
DATE:
A
S2014-1269
2014/06/23
SI BOARD LAYOUT AND ROUTING GUIDELINE
SHEET No.
FOR MICRO SAS-3 VERTICAL SURACE MOUNT
1
of
7
RECEPTACLE
CHECKED BY:
APPROVED BY:
DOCUMENT NUMBER:
CREATED / REVISED BY:
AS-78832-001
CMWONG 2014/06/23
HELVY 2014/06/23
WTCHUA 2014/06/23
TEMPLATE FILENAME: AS1704602.DOC
MICRO SAS-3 VERTICAL SMT RECEPTACLE
BOARD LAYOUT AND ROUTING GUIDELINES
1.0 SCOPE
This board layout and routing guidelines cover the printed circuit board layout that can be
used for the evaluation of high-speed signals using microstrip routing for 78832 series
connector.
Disclaimer:
Molex does not guarantee the performance of the final product to the
information provided in this document. All information in this report is considered Molex
proprietary and confidential. This guide is not intended as a substitute for engineering
analysis where optimization for signal integrity (SI) performance can be critical.
2.0 PC BOARD REQUIREMENTS
2.1 MATERIAL THICKNESS
The recommended PC board thickness shall be 1.00mm. Suitable PC board material shall
be glass epoxy (FR-4).
2.2 LAYOUT
The solder pads for the connector assembly must be precisely located to ensure proper
placement and optimum performance of the connector assembly. Refer to the applicable
Sales Drawing for the recommended solder pad pattern, dimensions and tolerances.
REVISION:
ECR/ECN INFORMATION: TITLE:
EC No:
DATE:
A
S2014-1269
2014/06/23
SI BOARD LAYOUT AND ROUTING GUIDELINE
SHEET No.
FOR MICRO SAS-3 VERTICAL SURACE MOUNT
2
of
7
RECEPTACLE
CHECKED BY:
APPROVED BY:
DOCUMENT NUMBER:
CREATED / REVISED BY:
AS-78832-001
CMWONG 2014/06/23
HELVY 2014/06/23
WTCHUA 2014/06/23
TEMPLATE FILENAME: AS1704602.DOC
MICRO SAS-3 VERTICAL SMT RECEPTACLE
BOARD LAYOUT AND ROUTING GUIDELINES
3.0 HIGH SPEED ROUTING
3.1 TRACE TO PAD ATTACHMENT
There are several ways to connect the traces to their corresponding signal pads. Two possible
methods are illustrated in Figures 1 and 2.
Figure 1
Figure 2
As seen in Figure 1, trace routed outwards from pad of connector will result in minimum pad stub
while worst case pad stub occurs when trace is routed inwards as shown in Figure 2.
REVISION:
ECR/ECN INFORMATION: TITLE:
EC No:
DATE:
A
S2014-1269
2014/06/23
SI BOARD LAYOUT AND ROUTING GUIDELINE
SHEET No.
FOR MICRO SAS-3 VERTICAL SURACE MOUNT
3
of
7
RECEPTACLE
CHECKED BY:
APPROVED BY:
DOCUMENT NUMBER:
CREATED / REVISED BY:
AS-78832-001
CMWONG 2014/06/23
HELVY 2014/06/23
WTCHUA 2014/06/23
TEMPLATE FILENAME: AS1704602.DOC
MICRO SAS-3 VERTICAL SMT RECEPTACLE
BOARD LAYOUT AND ROUTING GUIDELINES
3.2 GROUND VIA PLACEMENT
There are several ways to connect ground vias to their corresponding ground pads. Two possible
methods are illustrated in Figures 3 and 4.
PCB Top View
Ground
Via
Ground
Via
Figure 3
PCB Top View
“Run-away” Ground Via
Figure 4
As seen in Figure 3, ground vias can be attached to both ends of ground pad for better signal
return path. If this is not possible due to routing constrain, “run-away” ground vias from ground
pads should follow the direction where the signal traces were attached to their corresponding
signal pads as shown in Figure 4.
REVISION:
ECR/ECN INFORMATION: TITLE:
EC No:
DATE:
A
S2014-1269
2014/06/23
SI BOARD LAYOUT AND ROUTING GUIDELINE
SHEET No.
FOR MICRO SAS-3 VERTICAL SURACE MOUNT
4
of
7
RECEPTACLE
CHECKED BY:
APPROVED BY:
DOCUMENT NUMBER:
CREATED / REVISED BY:
AS-78832-001
CMWONG 2014/06/23
HELVY 2014/06/23
WTCHUA 2014/06/23
TEMPLATE FILENAME: AS1704602.DOC
MICRO SAS-3 VERTICAL SMT RECEPTACLE
BOARD LAYOUT AND ROUTING GUIDELINES
3.3 IMPEDANCE MATCHING AT TRACE AND FOOTPRINT/PAD
Impedance matching is critical to improve and optimize SI performance.
All traces and pad should design to obtain single-end 50Ω or differential 100Ω at
application.
This could be done by controlling distance between trace (H
trace
) and pad (H
pad
) with
reference to their ground return. This is illustrated in Figure 5.
When the trace width of pad equals to trace, H
trace
equals H
pad
. If pad width is wider than
trace, H
pad
> H
trace.
This is to eliminate excessive capacitive coupling at pad region.
Connector housing
pad
H
pad
H
trace
trace
PCB
Figure 5
REVISION:
ECR/ECN INFORMATION: TITLE:
EC No:
DATE:
A
S2014-1269
2014/06/23
SI BOARD LAYOUT AND ROUTING GUIDELINE
SHEET No.
FOR MICRO SAS-3 VERTICAL SURACE MOUNT
5
of
7
RECEPTACLE
CHECKED BY:
APPROVED BY:
DOCUMENT NUMBER:
CREATED / REVISED BY:
AS-78832-001
CMWONG 2014/06/23
HELVY 2014/06/23
WTCHUA 2014/06/23
TEMPLATE FILENAME: AS1704602.DOC
实时操作系统RTOS
