RE: [SI-LIST] : Edge Rates

Farrokh Mottahedin (Farrokh.Mottahedin@quantum.com)
Fri, 9 Jul 1999 08:47:12 -0700

Shouldn't we be discussing slew rate as opposed to edge rate? Most data
sheets define edge rate at 10-90% of rise time, but in certain other
standards (320 MByte/s LVD differential SCSI and others) it is strictly
20-80%.

Farrokh Mottahedin
Quantum Corporation
(408) 324-7934
farrokh.mottahedin@quantum.com

> -----Original Message-----
> From: Peterson, James F (FL51) [SMTP:jfpeterson@space.honeywell.com]
> Sent: Friday, July 09, 1999 7:54 AM
> To: 'si-list@silab.eng.sun.com'
> Subject: RE: [SI-LIST] : Edge Rates
>
> What seems to complicate my perspective on these super-fast edge rates is
> how they are effected by the load of the circuit. I believe that, without
> loading, most edge rates are sub-nano, but once loaded, they do slow down.
> Do we use this effective edge rate in our analysis or the raw edge rate?
> It
> seems that raw edge-rates might be conservative in certain practical
> situations. The only way I see of getting more realistic numbers, that
> could
> be applied in t-line analysis, is to have a good simulator that generates
> a
> waveform based on the driver and its environment (trace, loads, etc.)
> while
> distributing and lumping where appropriate.
>
> jim
>
> -----Original Message-----
> From: Dr. Edward P. Sayre [mailto:esayre@nesa.com]
> Sent: Friday, July 09, 1999 9:10 AM
> To: si-list@silab.eng.sun.com
> Subject: Re: [SI-LIST] : Edge Rates
>
>
> It has been an interesting set of developments over the last two years.
> Before we had one or two SI problems in a design, now every trace has the
> potential for SI problems.
>
> ed
> ======
> At 02:47 PM 7/8/99 -0700, you wrote:
> >I concur with Tom. It is highly unusual to see
> >a device these days that has an edge rate more
> >than 500 ps. This means that almost every pc
> >board trace must be considered a transmission line for
> >analysis purpose. Most devices manufactured today
> >also tend to have lower channel resistance than
> >necessary (10 to 25 ohms), which will cause severe
> >overshoot and ringback on unterminated nets.
> >
> >BTW, Tom also gives a great presentation with
> >a breakdown of the measured edgerate characteristics
> >of various devices.
> >
> >regards,
> >
> >scott
> >
> >
> >tomda wrote:
> >
> >> Assume 100 to 500 psec for the full transition for any modern logic
> family
> >> unless it has controlled edge rates.
> >>
> >> Tom Dagostino
> >>
> >> -----Original Message-----
> >> From: Ken Patterson [SMTP:ken.patterson@pathway-inc.com]
> >> Sent: Thursday, July 08, 1999 12:07 PM
> >> To: si-list@silab.eng.sun.com
> >> Subject: [SI-LIST] : Edge Rates
> >>
> >> I am a newcomer to signal integrity analysis and would like to know how
> >> to find out what the typical edge rates (i.e. rise and fall times) of
> >> some of the industry standard logic families are. These include FCT
> >> logic, SDRAMs and Syncburst SRAMs . I have an upcoming project that
> >> will use these devices and would loike to perform some signal integrity
> >> analysis.
> >>
> >> Ken Patterson
> >> Electronic Engineer
> >> ADC Broadband Communications/Pathway Division
> >> email:ken.patterson@pathway-inc.com
> >>
> >> **** To unsubscribe from si-list: send e-mail to
> >> majordomo@silab.eng.sun.com. In the BODY of message put: UNSUBSCRIBE
> >> si-list, for more help, put HELP. si-list archives are accessible at
> >> http://www.qsl.net/wb6tpu/si-list ****
> >>
> >> **** To unsubscribe from si-list: send e-mail to
> majordomo@silab.eng.sun.com. In the BODY of message put: UNSUBSCRIBE
> si-list, for more help, put HELP. si-list archives are accessible at
> http://www.qsl.net/wb6tpu/si-list ****
> >
> >
> >**** To unsubscribe from si-list: send e-mail to
> majordomo@silab.eng.sun.com. In the BODY of message put: UNSUBSCRIBE
> si-list, for more help, put HELP. si-list archives are accessible at
> http://www.qsl.net/wb6tpu/si-list ****
> >
> >
>
>
>
> +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~+
> | NORTH EAST SYSTEMS ASSOCIATES, INC. |
> | ------------------------------------- |
> | "High Performance Engineering & Design" |
> +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~+
> | Dr. Ed Sayre e-mail: esayre@nesa.com |
> | NESA, Inc. http://www.nesa.com/ |
> | 636 Great Road Tel +1.978.897-8787 |
> | Stow, MA 01775 USA Fax +1.978.897-5359 |
> +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~+
>
>
> **** To unsubscribe from si-list: send e-mail to
> majordomo@silab.eng.sun.com. In the BODY of message put: UNSUBSCRIBE
> si-list, for more help, put HELP. si-list archives are accessible at
> http://www.qsl.net/wb6tpu/si-list ****
>
> **** To unsubscribe from si-list: send e-mail to
> majordomo@silab.eng.sun.com. In the BODY of message put: UNSUBSCRIBE
> si-list, for more help, put HELP. si-list archives are accessible at
> http://www.qsl.net/wb6tpu/si-list ****

**** To unsubscribe from si-list: send e-mail to majordomo@silab.eng.sun.com. In the BODY of message put: UNSUBSCRIBE si-list, for more help, put HELP. si-list archives are accessible at http://www.qsl.net/wb6tpu/si-list ****