SFF specifications are available at http://www.snia.org/sff/specifications
or ftp://ftp.seagate.com/sff

This specification was developed by the SFF Committee prior to it
becoming the SFF TA (Technology Affiliate) TWG (Technical WorkingGroup) of SNIA (Storage Networking Industry Association).

The information below should be used instead of the equivalent herein.
POINTS OF CONTACT:
Chairman SFF TA TWG
Email: SFF-Chair@snia.org

If you are interested in participating in the activities of the SFF TWG, themembership application can be found at:
http://www.snia.org/sff/join
The complete list of SFF Specifications which have been completed or are currently
being worked on can be found at:
http://www.snia.org/sff/specifications/SFF-8000.TXT
The operations which complement the SNIA's TWG Policies & Procedures to guide the SFF
TWG can be found at:
http://www.snia.org/sff/specifications/SFF-8032.PDF
Suggestions for improvement of this specification will be welcome, they should besubmitted to:
http://www.snia.org/feedbackPublished

SFF-8665 Rev 1.9

SFF Committee documentation may be purchased in electronic form.
SFF specifications are available at ftp://ftp.seagate.com/sff

SFF Committee
SFF-8665
Specification for
QSFP+ 28 Gb/s 4X Pluggable Transceiver Solution (QSFP28)
Rev 1.9Secretariat:

June 29, 2015

SFF Committee

Abstract: This specification defines a 28 Gb/s QSFP+ pluggable transceiver solution
popularly known as QSFP28. It gathers the appropriate/unique Base Electrical, Optical,
Common Management, Module/Plug Formfactor, Host connector and cage specifications into aclearly delineated solution for users.
There are multiple generations of QSFP+Forwarded to Standardization
10 Gb/sQSFP10EIA-964/SFF-8436
Continuing Projects
10 Gb/sQSFP10
SFF-8635
14 Gb/sQSFP14SFF-8685
28 Gb/sQSFP28SFF-8665
Connectors compliant to SFF-8665 are also compliant to SFF-8685, and SFF-8635, but thereverse is not necessarily true.
This document provides a common specification for systems manufacturers, systemintegrators, and suppliers. This is an internal working document of the SFF Committee, anindustry ad hoc group.
This specification is made available for public review, and written comments aresolicited from readers. Comments received by the members will be considered for inclusion
in future revisions of this specification.
Support: This specification is supported by the identified member companies of the SFF
Committee.
POINTS OF CONTACT:Jay Neer
Molex Incorporated
2222 Wellington Court
Lisle, IL 60532

I. Dal Allan
Chairman SFF Committee
14426 Black Walnut Court
Saratoga CA 95070

Ph: 561-251-8016
Jay dot neer at molex dot com

Ph: 408-867-6630
endlcom at acm dot org

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EXPRESSION OF SUPPORT BY MANUFACTURERS

The following member companies of the SFF Committee voted in favor of this industry
specification.
Avago
EmulexFCI
Finisar
Foxconn
Hewlett Packard
HGST
JDS Uniphase
Molex
NetAppOclaro
PanduitTE Connectivity
Volex
The following member companies of the SFF Committee voted to abstain on this industryspecification.
Amphenol
Dell Computer
EMC
IBM
LSI
Luxshare-ICT
MGE
Pioneer
Sandisk
SeagateToshibaChange History
Rev 1.6:- Moved referenced SFF specs to 2.1 Industry Documents and expanded the list
- Added SFF-8672 and SFF-8683 to Figure 3-1 plus complementary sections- Added using interfaces to Application Specific Criteria
Rev 1.7- Clarified introductory paragraph of SFF-8662 and SFF-8672
Rev 1.8- Add multiple generations table to Abstract.
Rev 1.9- Modified Figure 3-1 to include explanatory details.

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SFF-8665 Rev 1.9Foreword
The development work on this specification was done by the SFF Committee, an industry
group. The membership of the committee since its formation in August 1990 has included amix of companies which are leaders across the industry.
When 2 1/2" diameter disk drives were introduced, there was no commonality on external
dimensions e.g. physical size, mounting locations, connector type, connector location,
between vendors.
The first use of these disk drives was in specific applications such as laptop portablecomputers and system integrators worked individually with vendors to develop thepackaging. The result was wide diversity, and incompatibility.
The problems faced by integrators, device suppliers, and component suppliers led to theformation of the SFF Committee as an industry ad hoc group to address the marketing andengineering considerations of the emerging new technology.
During the development of the form factor definitions, other activities were suggested
because participants in the SFF Committee faced more problems than the physical form
factors of disk drives. In November 1992, the charter was expanded to address any issuesof general interest and concern to the storage industry. The SFF Committee became a forum
for resolving industry issues that are either not addressed by the standards process orneed an immediate solution.
Those companies which have agreed to support a specification are identified in the firstpages of each SFF Specification. Industry consensus is not an essential requirement topublish an SFF Specification because it is recognized that in an emerging product area,
there is room for more than one approach. By making the documentation on competing
proposals available, an integrator can examine the alternatives available and select theproduct that is felt to be most suitable.
SFF Committee meetings are held during T10 weeks (see www.t10.org), and Specific Subject
Working Groups are held at the convenience of the participants. Material presented at SFF
Committee meetings becomes public domain, and there are no restrictions on the open
mailing of material presented at committee meetings.
Most of the specifications developed by the SFF Committee have either been incorporated
into standards or adopted as standards by EIA (Electronic Industries Association), ANSI(American National Standards Institute) and IEC (International ElectrotechnicalCommission).
If you are interested in participating or wish to follow the activities of the SFF
Committee, the signup for membership and/or documentation can be found at:www.sffcommittee.com/ie/join.html
The complete list of SFF Specifications which have been completed or are currently being
worked on by the SFF Committee can be found at:
ftp://ftp.seagate.com/sff/SFF-8000.TXT
If you wish to know more about the SFF Committee, the principles which guide theactivities can be found at:
ftp://ftp.seagate.com/sff/SFF-8032.TXT
Suggestions for improvement of this specification will be welcome. They should be sent tothe SFF Committee, 14426 Black Walnut Ct, Saratoga, CA 95070.

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12

3
4

Scope
1.1
Application Specific Criteria
References
2.1
Industry Documents
2.2
SFF Specifications
2.3
Sources
2.4
Conventions
Introduction
Overview of Referenced Specifications
4.1
SFF-8636
4.2
SFF-86614.3SFF-8662
4.4
SFF-8663 and SFF-8683
4.5
SFF-8672
4.6
SFF-8679

SFF-8665 Rev 1.9
CONTENTS

5555556788910111213

FIGURES
Figure 3-1 Specifications Needed to Implement a 28 Gb/s Pluggable Transceiver
Figure 4-1 Management Interface
Figure 4-2 Typical Cable Plug and Pluggable Module
Figure 4-3 SFF-8662 Host Connector Fixed Receptacle
Figure 4-4 SFF-8663 and SFF-8683 Pluggable Module Cages
Figure 4-5 SFF-8672 Host Connector Fixed Receptacle
Figure 4-6 Application Reference Model

78910111213

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SFF Committee -QSFP+ 28 Gb/s 4X Pluggable Transceiver Solution (QSFP28)
1

Scope

In an effort to broaden the applications for storage devices, an ad hoc industry group ofcompanies representing system integrators, peripheral suppliers, and component suppliers
decided to address the issues involved.
The SFF Committee was formed in August, 1990 and the first working document wasintroduced in January, 1991.
1.1 Application Specific Criteria
This solution is capable of meeting the interface requirements for the operation of:- InfiniBand IBTA EDR- IEEE 802.3bj 100 GbE
2References

2.1 Industry Documents
The following interface standards and specifications are relevant to this Specification.
- GR-253-CORE- IEEE Std 802.3bj 100 GbE- InfiniBand Architecture Specifications FDR and EDR- FC-PI-5, FC-PI-6- SAS-3- ESD specifications EN61000-4-2, JEDEC JESD22-A114-B- Optical Connectors: MPO:IEC 61754-7, Dual LC: IEC 61754-20- Aligned key (Type B) MPO patch cords: TIA-568- Dual LC optical patch cord: TIA/EIA-604-10A- Thermal specifications: NEBS GR-63- SFF-8636 Shielded Cables Common Management Interface- SFF-8661 QSFP+ 28 Gb/s 4X Pluggable Module- SFF-8662 QSFP+ 28 Gb/s 4X Connector (Style A)- SFF-8663 QSFP+ 28 Gb/s Cage (Style A)- SFF-8672 QSFP+ 28 Gb/s 4X Connector (Style B)- SFF-8679 QSFP+ 4X Base Specification- SFF-8683 QSFP+ 14 Gb/s Cage
2.2 SFF Specifications
There are several projects active within the SFF Committee. The complete list ofspecifications which have been completed or are still being worked on are listed in thespecification at ftp://ftp.seagate.com/sff/SFF-8000.TXT
2.3 Sources
Those who join the SFF Committee as an Observer or Member receive electronic copies ofthe minutes and SFF specifications (http://www.sffcommittee.com/ie/join.html).
Copies of ANSI standards may be purchased from the InterNational Committee forInformation Technology Standards (http://www.techstreet.com/incitsgate.tmpl).

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2.4 Conventions
The ISO convention of numbering is used i.e., the thousands and higher multiples areseparated by a space and a period is used as the decimal point. This is equivalent to theEnglish/American convention of a comma and a period.
American0.6
1,000
1,323,462.9

French0,6
1 000
1 323 462,9

QSFP+ 28 Gb/s 4X Pluggable Transceiver Solution

ISO0.61 000
1 323 462.9

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3SFF-8665 Rev 1.9

Introduction

This specification provides the required SFF specifications necessary to implement a 28Gb/s pluggable transceiver module. It includes mechanical specifications required by thehost i.e. the host connector, the host card cage and mechanical specifications of thepluggable module. In addition, the SFF specifications necessary to implement the module
management interface and the common electrical/optical base specifications are referenced
The specifications provide a common solution for combined four-channel ports that support
Ethernet and/or Fibre Channel and/or Infiniband and/or SAS and/or SONET/SDH
specifications. This specification encompasses design(s) capable of supporting multimodeand single mode modules, passive copper, active copper and active optical cables.
The Ethernet, Fibre Channel, InfiniBand, SAS, SONET/SDH, and other standards define
performance requirements on the characteristic impedance and ability to transmit multigigabit signals for cable assemblies and backplanes. The connectors used in suchapplications are subject to the requirements of the appropriate standard.
A flow chart of the required SFF specifications is shown in Figure 3-1.

IBTA EDRIEEE 802.3bj

SFF-8665

Application
Interface

Pluggable
Solution

SFF-8636

SFF-8661

SFF-8662

SFF-8663

SFF-8679

Management
Interface

Pluggable
ModuleConnector(Style A)

Cage(Style A)

GeneralElectrical

SFF-8672

SFF-8683

Connector(Style B)

Cage

FIGURE 3-1 SPECIFICATIONS NEEDED TO IMPLEMENT A 28 GB/S PLUGGABLE TRANSCEIVERQSFP+ 28 Gb/s 4X Pluggable Transceiver Solution

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Overview of Referenced Specifications

4.1 SFF-8636
The Shielded Cables Common Management Interface specification defines a common management
interface for 4-lane cable assemblies. It defines a common non-volatile memory map andprotocol utilized for managed external cable interface implementations.
Memory map details and communication protocol used to transfer the information aredescribed within this specification. This approach facilitates a common memory map andmanagement interface for applications with different mechanical, physical layer andotherwise different implementations.

FIGURE 4-1 MANAGEMENT INTERFACEQSFP+ 28 Gb/s 4X Pluggable Transceiver Solution

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4.2 SFF-8661
This specification defines the terminology and mechanical requirements for a pluggable
transceiver module/plug.
It is also intended to facilitate the implementation of 1 x "n" ganged and the 2 x "n"stacked cage configurations based on the mechanical form factor defined in thisspecification.

FIGURE 4-2 TYPICAL CABLE PLUG AND PLUGGABLE MODULE

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4.3 SFF-8662
This specification defines the physical interface and general performance requirements ofthe receptacle designed for use in high speed serial interconnect applications when
paired with SFF-8663.
The receptacle is used as the mating interface of the cable plug and pluggable module.

FIGURE 4-3 SFF-8662 HOST CONNECTOR FIXED RECEPTACLEQSFP+ 28 Gb/s 4X Pluggable Transceiver Solution

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4.4 SFF-8663 and SFF-8683
The mechanical dimensioning of the cages provides backwards mechanical compatibility
between generations of cable plugs and pluggable modules.
SFF-8663 facilitates the implementation of 1 x "n" ganged cages and the 2 x "n" stacked
cage configurations.

FIGURE 4-4 SFF-8663 AND SFF-8683 PLUGGABLE MODULE CAGESQSFP+ 28 Gb/s 4X Pluggable Transceiver Solution

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4.5 SFF-8672
This specifications defines the physical interface and general performance requirementsof the receptacle designed for use in high speed serial interconnect applications when
paired with SFF-8683.
The receptacle is used as the mating interface of the cable plug and pluggable module.

FIGURE 4-5 SFF-8672 HOST CONNECTOR FIXED RECEPTACLEQSFP+ 28 Gb/s 4X Pluggable Transceiver Solution

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4.6 SFF-8679
This specification defines the pin outs, the electrical, the optical, the power supply,
the ESD and the thermal characteristics of the cable plugs and pluggable modules.

FIGURE 4-6 APPLICATION REFERENCE MODELQSFP+ 28 Gb/s 4X Pluggable Transceiver Solution

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