Minutes of SAS PHY Working Group conference call May26, 2011T10/11-262r0

Attendance:

Mr. Min-Jie ChongAgilent Technologies

Mr. Mickey FeltonEMC

Mr. Douglas WagnerFCI

Mr. Andrew ZambellFCI

Mr. Fred FonsFoxconn Electronics

Mr. Barry OlawskyHewlett Packard Co.

Mr. Dan ColegroveHitachi Global Storage Tech.

Mr. Paul LarsonHitachi Global Storage Tech.

Mr. Jay DiepenbrockIBM Corp.

Dr. Mark SeidelIntel Corp.

Mr. Rich MellitzIntel Corp.

Mr. Joel SilvermanKawasaki Microelectronics

Mr. Harvey NewmanLSI Corp.

Mr. Gabriel RomeroLSI Corp.

Mr. Bill VoorheesLSI Corp.

Mr. Paul WassenbergMarvell Semiconductor, Inc.

Mr. Kevin WittMaxim Semiconductor

Mr. Vasilis PapanikolaouMindspeed

Mr. Galen FrommMolex Inc.

Mr. Michael RostMolex Inc.

Mr. Mathieu GagnonPMC-Sierra

Mr. Tim SymonsPMC-Sierra

Mr. Alvin CoxSeagate Technology

Mr. RaymondPavlakSeagate Technology

Mr. Allen KramerSeagate Technology

Mr. John SawdySiemon

Mr. Mike FitzpatrickToshiba

Mr. Joel MeyersTE Connectivity

Mr. Scott ShueyTE Connectivity

Mr. Toney ChewVolex, Inc.

Mr. Henry KuoWDC

Mr. Steve FinchWDC

Mr. Ramya DissanayakeWDC

Mr. Alan WestburyXyratex

Mr. Tim GroomXyratex

Mr. Charles Jarboe

36 in attendance

Agenda:

AC coupling capacitor requirements:

Discussed the AC coupling requirements. The issue exists with SATA Gen1i allowing the option for DC coupling. To gain channel margin at 12G, AC coupling could be accomplished with only one capacitor between the transmitter and receiver. Previous SAS-only internal implementations allowed for SAS-only domain items, such as a drive to have AC coupling only on the receiver. The transmitter on many of these devices is DC coupled with the AC coupling provided by the receiver at the other end. The question came up regarding the separation of internal and external. Alvin looked at the original SAS phy specification draft material and found that AC coupling on transmitter for external connections and for expanders has always been a requirement.

Mark Seidel plans to write a proposal to change the transmitter AC coupling requirement. The requirement for 12G would need to state that the capacitor is not allowed on the transmitter to provide the desired channel advantage for 12G.

PMC voiced concern regarding the possible shorting issues with the transmitter not AC coupled. There is a characteristic impedance of the termination, but Alvin indicated that, as editor, he did not think that adding specification requirements for non-compliant attachment cases was reasonable. If PMC wishes to add such requirements, submit a proposal.

The AC coupling cap ESR requirements:

The current note states: “The equivalent series resistance at 3 GHz should be less than 1 ohm.”The discussion pointed to possible other parameters such as the inductance rather than the resistance. Also mentioned was Q and resonance. Mickey indicated he is working on a presentation to show what he has found regarding capacitor specifications. That should be available for the next call.

SSC requirements:

How much SSC is needed?1,000 ppm is probably sufficient for 12G. Intel made a presentation regarding SSC when 6G was being developed I believe this was in January of 2004, but I cannot find the presentation. In 06-064r2, HP indicated that the data was not conclusive. Barry is gathering information to provide a new look at the effects of SSC. His comment was that the effectiveness of real world are not incremental as compared to ideal.

Connector updates:

None.

Channel analysis updates:

There was a quick review10-361r3 explaining the SAS3_EYEOPENING method along with updated results. The latest script still needs some cleanup, so it is not posted yet.

We also reviewed parts of11-119r1which compares the 3 different channel analysis methods (SAS3_EYEOPENING, IBIS-AMI & ISAS_Chan2L). This discusses spec’s do’s & don’ts, questions of how many usage models are required, and where should the compliance points be. The discussion ended on page 15 with discussion about the usage model. Previous versions of the standard have required the phys to be capable of performing with the maximum overall channel loss. The multiple usage model concept is promoting a scaled phy capability based on specific application models. Should we stay with “one size fits all” or should we embrace multiple phy capabilities?

SAS-3 Electrical Spec (11-221r2) [Witt]

Not reviewed due to lack of time.

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Webex information:
Topic: SAS PHY WG
Date: Thursday, June 2, 2011
Time: 10:00 am, Central Daylight Time (Chicago, GMT-05:00)
Meeting Number: 826 515 680
Meeting Password: newsas

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