Message

=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D

-----Original Message-----
From: Muranyi, Arpad=20
Sent: Tuesday, May 13, 2003 9:37 AM
To:=20 ibis-users@eda.org
Subject: RE: [IBIS-Users]=20 (lv)pecl

Eric,

The=20 question is not so much what the IBIS simulator does with=20 the

clamp=20 information, but what is the function of the = clamps in=20 real

life? =20 If=20 you understand the second part, you will also = understand

the=20 first.

The short=20 answer is that it will clip signals that go beyond = the

rails, hence=20 the name "clamp". Regarding the resistance = question,

usually the=20 problem is that SPICE models do not include the = resistive

properties=20 of the diodes, so you get an ideal diode with no = series

resistance. This resistance is usually = in the low=20 Ohms, but it

depends on=20 the design. If you have a SPICE model that uses = ideal

diodes, you=20 can add a small value resistor in series with the = diode

to avoid=20 those high currents.

Arpad

=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D

-----Original Message-----
From: = erik.van.der.ven@philips.com=20 [mailto:erik.van.der.ven@philips.com]
Sent: Tuesday, May 13, = 2003 1:50=20 AM
To: ibis-users@eda.org
Subject: RE: [IBIS-Users]=20 (lv)pecl

As Tom = and Fred=20 suggest I have to add "some" resistance to the clamp diodes to prevent = high=20 currents. Must these device models be characterised or should I just add = an=20 arbitrary value. If so what will be the value of this information. I = still don't=20 have the insight what an IBIS simulator does do with the clamping info?=20

With kind = regards,=20

Ir. Erik van der = Ven
Room=20 DB1032
Business Line Networking Infrastructure
Philips = Semiconductors=20 BV
Gerstweg 2
6534 AE Nijmegen
The Netherlands
Phone:=20 +31-24-3534334

"Tom = Dagostino"=20 <tom@teraspeed.com>=20

05/12/03 06:41 PM =
Please respond to tom

=
To: = =20 Erik van der=20 = Ven/NYM/SC/PHILIPS@EMEA2
<ibis-users@server.eda.org>=20
= cc: =20
=20 Subject: RE: [IBIS-Users] = (lv)pecl=20

=20 Classification: =20

Erik
=20
Fred is right that for an = ECL model that=20 the voltage range that has to be characterized is over the 0 to Vcc - 2V = range=20 in the table. I like to see at least the active region between 0 = and Vcc=20 modeled. There are some ECL parts that will not be adequately=20 characterized by only going from 0 to Vcc - 2V. If I remember = correctly ON=20 Semi makes some ECL line drivers that have about twice the swing of = normal=20 ECL.
=
Fred, the garbage Erik referred to = was multiple=20 lines in the tables that have the same voltage values and zero current.=20 I've seen models with this before but I don't remember the = cause of=20 it.
=
Yes, IBIS likely goes too far into = the clamp=20 regions for characterization. If your clamp currents are extreme = it is=20 likely that the clamp diodes have not been properly characterized in = their SPICE=20 models. If you are seeing more than a few amperes in the clamps = you can=20 assume the intrinsic resistance of the diodes, the metal, etc. have not = been=20 fully characterized. To eliminate this try adding a few hundred = milli Ohms=20 in series with the clamps to bring the currents down to a more realistic = level.
=
Tom Dagostino
Teraspeed Consulting Group LLC Teraspeed = Consulting Group=20 LLC
2926 SE Yamhill St. = =20 Device Modeling Division =
Portland, OR 97214 = =20 13610 SW Harness Lane =
= =20 =20 Beaverton, OR 97008
http://www.teraspeed.com = 503-430-1065=20

tom@teraspeed.com
-----Original=20 Message-----
From: owner-ibis-users@server.eda.org=20 [mailto:owner-ibis-users@server.eda.org]On Behalf Of=20 erik.van.der.ven@philips.com
Sent: Monday, May 12, 2003 = 1:44=20 AM
To: ibis-users@server.eda.org
Subject: Re: = [IBIS-Users]=20 (lv)pecl

Dear = Fred,

Thank=20 you for your reply. About the garbage; I explained it in an email I just = sent=20 (directed to Tom). =

The s2ibis program does not generate IV- = tables from=20 0-2.2V, but the program that has been modified by my collegue does do = this=20 (apart from the "garbage" that both programs produce).
Is this=20 range enough? According to Tom it should be -3.3-6.6V. Where is this = range for=20 ECL/PECL defined? I cannot find it in the specification.

When=20 the voltage is out of the normal operating range the currents can be = very high,=20 even so high that the transistor models are not valid anymore. What is = the use=20 of specifying these currents? Can they be left out? If not, what is done = with=20 this information. =
I have the same question for the clamp = currents. The=20 output can be disabled, so this is a kind of tri-state (not really high=20 impedant). Also here the currents are unrealistically high. What is done = with=20 this information? Why must it be specified? The PECL voltage swing is = such that=20 even a fully reflected signal will not cause the output to be outside = the supply=20 range.

With kind regards,

Ir. = Erik van der=20 Ven
Room DB1032
Business Line Networking Infrastructure
Philips = Semiconductors BV
Gerstweg 2
6534 AE Nijmegen
The = Netherlands
Phone:=20 +31-24-3534334 =

Fred=20 Balistreri <fred@apsimtech.com>
Sent by:=20
fred@interjet.apsimtech.com=20
05/09/03 07:10 PM
= =20
= To:=20 Erik van der=20 Ven/NYM/SC/PHILIPS@EMEA2=20
= cc:=20 =20
=20 Subject: Re: [IBIS-Users]=20 (lv)pecl
=20 Classification: =

Erik, you need to define what convention you are
using = when you=20 say voltage range. Remember that
for ECL and PECL both the pullup and = pulldown
reference is the same. If the voltage range
you refer to = is the=20 IBIS Vtable then your
range is not correct. Under the IBIS = conventions
for=20 ECL or PECL type Vtable=3D Vcc - Vout.
This is true for both = pullup/pulldown=20 for PECL/ECL.
IBIS further explains that for ECL, PECL the
range = should be=20 VCC - 2.2 volts. Under the
IBIS rules then the range should always = be
0 -=20 2.2 volts for both pullup and pulldown.
Note that 0 really means 3.3 = at the=20 output
for your case and 2.2 really means 1.1 at = the
output.

I=20 don't quite understand your problem. You state
garbage. It's probably = not=20 quite descriptive
enough to understand your issue. Although = the
meaning=20 is clear.

Best Regards,

erik.van.der.ven@philips.com=20 wrote:
>
> Part 1.1Type: Plain Text=20 (text/plain)

--
Fred=20 Balistreri
fred@apsimtech.com

http://www.apsimtech.com

- ------_=_NextPart_001_01C3196E.99415B00-- |------------------------------------------------------------------ |For help or to subscribe/unsubscribe, email majordomo@eda.org |with just the appropriate command message(s) in the body: | | help | subscribe ibis | subscribe ibis-users | unsubscribe ibis | unsubscribe ibis-users | |or email a written request to ibis-request@eda.org. | |IBIS reflector archives exist under: | | http://www.eda.org/pub/ibis/email_archive/ Recent | http://www.eda.org/pub/ibis/users_archive/ Recent | http://www.eda.org/pub/ibis/email/ E-mail since 1993 ------------------------------ Date: Tue, 13 May 2003 09:37:27 -0700 From: "Muranyi, Arpad" Subject: RE: [IBIS-Users] (lv)pecl This is a multi-part message in MIME format. - ------_=_NextPart_001_01C3196D.F0909926 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Eric, =20 The question is not so much what the IBIS simulator does with the clamp information, but what is the function of the clamps in real life? If you understand the second part, you will also understand the first. =20 The short answer is that it will clip signals that go beyond the rails, hence the name "clamp". Regarding the resistance question, usually the problem is that SPICE models do not include the resistive properties of the diodes, so you get an ideal diode with no series resistance. This resistance is usually in the low Ohms, but it depends on the design. If you have a SPICE model that uses ideal diodes, you can add a small value resistor in series with the diode to avoid those high currents. =20 Arpad =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =20 =20 =20 - -----Original Message----- From: erik.van.der.ven@philips.com [mailto:erik.van.der.ven@philips.com] Sent: Tuesday, May 13, 2003 1:50 AM To: ibis-users@eda.org Subject: RE: [IBIS-Users] (lv)pecl As Tom and Fred suggest I have to add "some" resistance to the clamp = diodes to prevent high currents. Must these device models be = characterised or should I just add an arbitrary value. If so what will = be the value of this information. I still don't have the insight what an = IBIS simulator does do with the clamping info?=20 With kind regards,=20 Ir. Erik van der Ven Room DB1032 Business Line Networking Infrastructure Philips Semiconductors BV Gerstweg 2 6534 AE Nijmegen The Netherlands Phone: +31-24-3534334=20 =09 "Tom Dagostino" =20 05/12/03 06:41 PM=20 Please respond to tom=20 =20 To: Erik van der Ven/NYM/SC/PHILIPS@EMEA2 =20 cc: =20 Subject: RE: [IBIS-Users] (lv)pecl=20 Classification: =20 Erik=20 =20 Fred is right that for an ECL model that the voltage range that has to = be characterized is over the 0 to Vcc - 2V range in the table. I like = to see at least the active region between 0 and Vcc modeled. There are = some ECL parts that will not be adequately characterized by only going = from 0 to Vcc - 2V. If I remember correctly ON Semi makes some ECL line = drivers that have about twice the swing of normal ECL.=20 =20 Fred, the garbage Erik referred to was multiple lines in the tables that = have the same voltage values and zero current. I've seen models with = this before but I don't remember the cause of it.=20 =20 Yes, IBIS likely goes too far into the clamp regions for = characterization. If your clamp currents are extreme it is likely that = the clamp diodes have not been properly characterized in their SPICE = models. If you are seeing more than a few amperes in the clamps you can = assume the intrinsic resistance of the diodes, the metal, etc. have not = been fully characterized. To eliminate this try adding a few hundred = milli Ohms in series with the clamps to bring the currents down to a = more realistic level.=20 =20 Tom Dagostino=20 Teraspeed Consulting Group LLC Teraspeed Consulting Group LLC=20 2926 SE Yamhill St. Device Modeling Division=20 Portland, OR 97214 13610 SW Harness Lane=20 Beaverton, OR 97008=20 http://www.teraspeed.com 503-430-1065=20 tom@teraspeed.com=20 - -----Original Message----- From: owner-ibis-users@server.eda.org = [mailto:owner-ibis-users@server.eda.org]On Behalf Of = erik.van.der.ven@philips.com Sent: Monday, May 12, 2003 1:44 AM To: ibis-users@server.eda.org Subject: Re: [IBIS-Users] (lv)pecl Dear Fred,=20 Thank you for your reply. About the garbage; I explained it in an email = I just sent (directed to Tom).=20 The s2ibis program does not generate IV- tables from 0-2.2V, but the = program that has been modified by my collegue does do this (apart from = the "garbage" that both programs produce).=20 Is this range enough? According to Tom it should be -3.3-6.6V. Where is = this range for ECL/PECL defined? I cannot find it in the specification.=20 When the voltage is out of the normal operating range the currents can = be very high, even so high that the transistor models are not valid = anymore. What is the use of specifying these currents? Can they be left = out? If not, what is done with this information.=20 I have the same question for the clamp currents. The output can be = disabled, so this is a kind of tri-state (not really high impedant). = Also here the currents are unrealistically high. What is done with this = information? Why must it be specified? The PECL voltage swing is such = that even a fully reflected signal will not cause the output to be = outside the supply range.=20 With kind regards,=20 Ir. Erik van der Ven Room DB1032 Business Line Networking Infrastructure Philips Semiconductors BV Gerstweg 2 6534 AE Nijmegen The Netherlands Phone: +31-24-3534334=20 =09 Fred Balistreri =20 Sent by:=20 fred@interjet.apsimtech.com=20 05/09/03 07:10 PM=20 =20 To: Erik van der Ven/NYM/SC/PHILIPS@EMEA2=20 cc: =20 Subject: Re: [IBIS-Users] (lv)pecl=20 Classification: =20 Erik, you need to define what convention you are using when you say voltage range. Remember that for ECL and PECL both the pullup and pulldown reference is the same. If the voltage range you refer to is the IBIS Vtable then your range is not correct. Under the IBIS conventions for ECL or PECL type Vtable=3D Vcc - Vout. This is true for both pullup/pulldown for PECL/ECL. IBIS further explains that for ECL, PECL the range should be VCC - 2.2 volts. Under the IBIS rules then the range should always be 0 - 2.2 volts for both pullup and pulldown. Note that 0 really means 3.3 at the output for your case and 2.2 really means 1.1 at the output. I don't quite understand your problem. You state garbage. It's probably not quite descriptive=20 enough to understand your issue. Although the meaning is clear. Best Regards, erik.van.der.ven@philips.com wrote: >=20 > Part 1.1Type: Plain Text (text/plain) - --=20 Fred Balistreri fred@apsimtech.com http://www.apsimtech.com - ------_=_NextPart_001_01C3196D.F0909926 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Eric,

The=20 question is not so much what the IBIS simulator does with=20 the

clamp=20 information, but what is the function of the = clamps in=20 real

life? =20 If=20 you understand the second part, you will also = understand

the=20 first.

The short=20 answer is that it will clip signals that go beyond = the

rails, hence=20 the name "clamp". Regarding the resistance = question,

usually the=20 problem is that SPICE models do not include the = resistive

properties=20 of the diodes, so you get an ideal diode with no = series

resistance. This resistance is usually = in the low=20 Ohms, but it

depends on=20 the design. If you have a SPICE model that uses = ideal

diodes, you=20 can add a small value resistor in series with the = diode

to avoid=20 those high currents.

Arpad

"Tom = Dagostino"=20 <tom@teraspeed.com>=20

05/12/03 06:41 PM =
Please respond to tom

=
To: = =20 Erik van der=20 = Ven/NYM/SC/PHILIPS@EMEA2
<ibis-users@server.eda.org>=20
= cc: =20
=20 Subject: RE: [IBIS-Users] = (lv)pecl=20

=20 Classification: =20

- ------_=_NextPart_001_01C3196D.F0909926-- |------------------------------------------------------------------ |For help or to subscribe/unsubscribe, email majordomo@eda.org |with just the appropriate command message(s) in the body: | | help | subscribe ibis | subscribe ibis-users | unsubscribe ibis | unsubscribe ibis-users | |or email a written request to ibis-request@eda.org. | |IBIS reflector archives exist under: | | http://www.eda.org/pub/ibis/email_archive/ Recent | http://www.eda.org/pub/ibis/users_archive/ Recent | http://www.eda.org/pub/ibis/email/ E-mail since 1993 ------------------------------ Date: Tue, 13 May 2003 11:20:34 +0200 From: erik.van.der.ven@philips.com Subject: [IBIS-Users] differential output modeling This is a multipart message in MIME format. - --=_alternative 003381D7C1256D25_= Content-Type: text/plain; charset="us-ascii" I have some problems on how to model a differential output. In my case it is a lvpecl output. The output swing is controlled by an internal feedback loop. I noticed that when I simulate the pull-up/pull-down curves of the non-inverting outputs the results are dependent on the termination of the inverting output (resistor, voltage). So these outputs obviously influence each other. So question is what to do with the output that is not being modeled? It seems that this situation is simular to LVDS outputs. A method that I have seen is to connect a voltage source to the inverting output, such that the sum of both voltages divided by 2 equals the common mode voltage during normal operation. I observe that the currents in the inverting output become very large and are therefore still likely to influence the result of the non-inverting output. The motivation for this method was to approach behaviour during normal operation. But I think this is not the case, since the outputs are forced in a state that does not comply to the logic state as forced by the input signal. Has anyone experience with this? With kind regards, Ir. Erik van der Ven Room DB1032 Business Line Networking Infrastructure Philips Semiconductors BV Gerstweg 2 6534 AE Nijmegen The Netherlands Phone: +31-24-3534334 - --=_alternative 003381D7C1256D25_= Content-Type: text/html; charset="us-ascii"
I have some problems on how to model a differential output.
In my case it is a lvpecl output.
The output swing is controlled by an internal feedback loop.
I noticed that when I simulate the pull-up/pull-down curves of the non-inverting outputs the results are dependent on the termination of the inverting output (resistor, voltage).
So these outputs obviously influence each other.
So question is what to do with the output that is not being modeled?

It seems that this situation is simular to LVDS outputs.
A method that I have seen is to connect a voltage source to the inverting output, such that the sum of both voltages divided by 2 equals the common mode voltage during normal operation.
I observe that the currents in the inverting output become very large and are therefore still likely to influence the result of the non-inverting output.
The motivation for this method was to approach behaviour during normal operation. But I think this is not the case, since the outputs are forced in a state that does not comply to the logic state as forced by the input signal.

Has anyone experience with this?

With kind regards,

Ir. Erik van der Ven
Room DB1032
Business Line Networking Infrastructure
Philips Semiconductors BV
Gerstweg 2
6534 AE Nijmegen
The Netherlands
Phone: +31-24-3534334 - --=_alternative 003381D7C1256D25_=-- |------------------------------------------------------------------ |For help or to subscribe/unsubscribe, email majordomo@eda.org |with just the appropriate command message(s) in the body: | | help | subscribe ibis | subscribe ibis-users | unsubscribe ibis | unsubscribe ibis-users | |or email a written request to ibis-request@eda.org. | |IBIS reflector archives exist under: | | http://www.eda.org/pub/ibis/email_archive/ Recent | http://www.eda.org/pub/ibis/users_archive/ Recent | http://www.eda.org/pub/ibis/email/ E-mail since 1993 ------------------------------ Date: Tue, 13 May 2003 13:07:02 +0200 From: erik.van.der.ven@philips.com Subject: [IBIS-Users] Delayed Mail (still being retried) This is the Postfix program at host gw-nl5.philips.com. #################################################################### # THIS IS A WARNING ONLY. YOU DO NOT NEED TO RESEND YOUR MESSAGE. # #################################################################### Your message could not be delivered for 2.0 hours. It will be retried until it is 3.0 days old. For further assistance, please send mail to The Postfix program : Name service error for name=eda.org type=MX: Host not found, try again Reporting-MTA: dns; gw-nl5.philips.com Arrival-Date: Tue, 13 May 2003 10:52:31 +0200 (MET DST) Final-Recipient: rfc822; ibis-users@eda.org Action: delayed Status: 4.0.0 Diagnostic-Code: X-Postfix; Name service error for name=eda.org type=MX: Host not found, try again Will-Retry-Until: Fri, 16 May 2003 10:52:31 +0200 (MET DST) Received: from smtpscan-nl3.philips.com (smtpscan-nl3.philips.com [130.139.36.23]) by gw-nl5.philips.com (Postfix) with ESMTP id 8DFCE5AF2A for ; Tue, 13 May 2003 10:52:31 +0200 (MET DST) Received: from smtprelay-nl2.philips.com (localhost [127.0.0.1]) by smtpscan-nl3.philips.com (8.9.3-p1/8.8.5-1.2.2m-19990317) with ESMTP id KAA26646 for ; Tue, 13 May 2003 10:52:23 +0200 (MET DST) From: erik.van.der.ven@philips.com Received: from ehv001soh.diamond.philips.com (e2soh01.diamond.philips.com [130.139.52.13]) by smtprelay-nl2.philips.com (8.9.3p2/8.8.5-1.2.2m-19990317) with ESMTP id KAA23280 for ; Tue, 13 May 2003 10:51:54 +0200 (MEST) To: ibis-users@eda.org Subject: RE: [IBIS-Users] (lv)pecl MIME-Version: 1.0 X-Mailer: Lotus Notes Release 5.0.9a January 7, 2002 Message-ID: Date: Tue, 13 May 2003 10:49:50 +0200 X-MIMETrack: Serialize by Router on ehv001soh/H/SERVER/PHILIPS(Release 5.0.9a |January 7, 2002) at 13/05/2003 10:50:12, Serialize complete at 13/05/2003 10:50:12 Content-Type: multipart/alternative; boundary="=_alternative 0030B147C1256D25_=" |------------------------------------------------------------------ |For help or to subscribe/unsubscribe, email majordomo@eda.org |with just the appropriate command message(s) in the body: | | help | subscribe ibis | subscribe ibis-users | unsubscribe ibis | unsubscribe ibis-users | |or email a written request to ibis-request@eda.org. | |IBIS reflector archives exist under: | | http://www.eda.org/pub/ibis/email_archive/ Recent | http://www.eda.org/pub/ibis/users_archive/ Recent | http://www.eda.org/pub/ibis/email/ E-mail since 1993 ------------------------------ Date: Tue, 13 May 2003 15:12:28 -0400 From: Robert Haller Subject: Re: [IBIS-Users] Validating IBIS Inputs Tim, One way to verify IBIS input buffer clamps is by running a simulations using a ideal voltage source driving through a low resistance and high etch impedance. i.e. Voltage source of V=Vdd, Tr = 500ps,resistor of 10 ohms and a Tline of Zo=75 ohms/TD=4ns,and/or 1ns. The clamps will turn on because the signal will overshoot at the end of the line. By utilizing ideal circuit elements you have eliminated all the other variables. You will also be able to validate the input capacitance of your receiver. The choice of 75 ohms impedance of the transmission line is not critical. The impedance must be high enough to guarantee turning on the clamps. The combination of the driver output impedance and the transmission line forms a voltage divider, which defines the initial amplitude as the wave leaves the driver. When the wave reaches the end of the unterminated transmission line it doubles. You can compare your IBIS simulations to Spice or bench or both. For more information refer to "Constructing Accurate Behavioral Models of I/O Buffers" ISBN 0-933-217-47-1 Designcon98 (HPSDC). regards. Bob - -- Robert J. Haller (rhaller@sisoft.com) Principal Consultant Signal Integrity Software Inc. 6 Clock Tower Place, Suite 250 Maynard, MA 01754 Phone: (978) 461-0449, ext 15 Timothy Coyle wrote: > Hello, > I'm curious as to how other people validate an IBIS input buffer with a ground clamp and power clamp curve to the original > SPICE netlist. If I run a simulation of a driver and receiver with a transmission line, and then a driver with a transmission > line and a lumped capacitor load, I get almost the same result. (Assuming a properly made IBIS file) The power and ground clamp > curves only turn on below Reference Ground or above supply voltage. So if I have an input going into my input buffer that has overshoot > then should I see my powerclamp curve turn on? What types of tests do people do to validate that the clamps are behaving as expected? > (And feel free to inform me on what the expected behavior of the clamps should be) > > Thanks in advance, > > Tim > |------------------------------------------------------------------ > |------------------------------------------------------------------ |For help or to subscribe/unsubscribe, email majordomo@eda.org |with just the appropriate command message(s) in the body: | | help | subscribe ibis | subscribe ibis-users | unsubscribe ibis | unsubscribe ibis-users | |or email a written request to ibis-request@eda.org. | |IBIS reflector archives exist under: | | http://www.eda.org/pub/ibis/email_archive/ Recent | http://www.eda.org/pub/ibis/users_archive/ Recent | http://www.eda.org/pub/ibis/email/ E-mail since 1993 ------------------------------ Date: Wed, 14 May 2003 08:28:26 +0200 From: erik.van.der.ven@philips.com Subject: [IBIS-Users] Delayed Mail (still being retried) This is the Postfix program at host gw-nl6.philips.com. #################################################################### # THIS IS A WARNING ONLY. YOU DO NOT NEED TO RESEND YOUR MESSAGE. # #################################################################### Your message could not be delivered for 2.0 hours. It will be retried until it is 3.0 days old. For further assistance, please send mail to The Postfix program : Name service error for name=eda.org type=MX: Host not found, try again Reporting-MTA: dns; gw-nl6.philips.com Arrival-Date: Tue, 13 May 2003 11:22:39 +0200 (MET DST) Final-Recipient: rfc822; ibis-users@eda.org Action: delayed Status: 4.0.0 Diagnostic-Code: X-Postfix; Name service error for name=eda.org type=MX: Host not found, try again Will-Retry-Until: Fri, 16 May 2003 11:22:39 +0200 (MET DST) Received: from smtpscan-nl2.philips.com (smtpscan-nl2.philips.com [130.139.36.22]) by gw-nl6.philips.com (Postfix) with ESMTP id 3A5195F4DD for ; Tue, 13 May 2003 11:22:39 +0200 (MET DST) Received: from smtprelay-nl2.philips.com (localhost [127.0.0.1]) by smtpscan-nl2.philips.com (8.9.3-p1/8.8.5-1.2.2m-19990317) with ESMTP id LAA05980 for ; Tue, 13 May 2003 11:22:38 +0200 (MET DST) From: erik.van.der.ven@philips.com Received: from ehv001soh.diamond.philips.com (e2soh01.diamond.philips.com [130.139.52.13]) by smtprelay-nl2.philips.com (8.9.3p2/8.8.5-1.2.2m-19990317) with ESMTP id LAA11153 for ; Tue, 13 May 2003 11:22:38 +0200 (MEST) To: ibis-users@eda.org Subject: differential output modeling MIME-Version: 1.0 X-Mailer: Lotus Notes Release 5.0.9a January 7, 2002 Message-ID: Date: Tue, 13 May 2003 11:20:34 +0200 X-MIMETrack: Serialize by Router on ehv001soh/H/SERVER/PHILIPS(Release 5.0.9a |January 7, 2002) at 13/05/2003 11:20:55, Serialize complete at 13/05/2003 11:20:55 Content-Type: multipart/alternative; boundary="=_alternative 003381D7C1256D25_=" |------------------------------------------------------------------ |For help or to subscribe/unsubscribe, email majordomo@eda.org |with just the appropriate command message(s) in the body: | | help | subscribe ibis | subscribe ibis-users | unsubscribe ibis | unsubscribe ibis-users | |or email a written request to ibis-request@eda.org. | |IBIS reflector archives exist under: | | http://www.eda.org/pub/ibis/email_archive/ Recent | http://www.eda.org/pub/ibis/users_archive/ Recent | http://www.eda.org/pub/ibis/email/ E-mail since 1993 ------------------------------ Date: Wed, 14 May 2003 08:28:33 +0200 From: erik.van.der.ven@philips.com Subject: [IBIS-Users] Delayed Mail (still being retried) This is the Postfix program at host gw-nl5.philips.com. #################################################################### # THIS IS A WARNING ONLY. YOU DO NOT NEED TO RESEND YOUR MESSAGE. # #################################################################### Your message could not be delivered for 2.0 hours. It will be retried until it is 3.0 days old. For further assistance, please send mail to The Postfix program : Name service error for name=eda.org type=MX: Host not found, try again Reporting-MTA: dns; gw-nl5.philips.com Arrival-Date: Tue, 13 May 2003 13:09:09 +0200 (MET DST) Final-Recipient: rfc822; ibis-users@eda.org Action: delayed Status: 4.0.0 Diagnostic-Code: X-Postfix; Name service error for name=eda.org type=MX: Host not found, try again Will-Retry-Until: Fri, 16 May 2003 13:09:09 +0200 (MET DST) Received: from smtpscan-nl1.philips.com (smtpscan-nl1.philips.com [130.139.36.21]) by gw-nl5.philips.com (Postfix) with ESMTP id E9EF888D6B for ; Tue, 13 May 2003 13:09:08 +0200 (MET DST) Received: from smtprelay-nl2.philips.com (localhost [127.0.0.1]) by smtpscan-nl1.philips.com (8.9.3-p1/8.8.5-1.2.2m-19990317) with ESMTP id NAA16414 for ; Tue, 13 May 2003 13:09:08 +0200 (MET DST) From: erik.van.der.ven@philips.com Received: from ehv001soh.diamond.philips.com (e2soh01.diamond.philips.com [130.139.52.13]) by smtprelay-nl2.philips.com (8.9.3p2/8.8.5-1.2.2m-19990317) with ESMTP id NAA03449 for ; Tue, 13 May 2003 13:09:07 +0200 (MEST) MIME-Version: 1.0 Subject: Delayed Mail (still being retried) To: Message-ID: Date: Tue, 13 May 2003 13:07:02 +0200 X-MIMETrack: Serialize by Router on ehv001soh/H/SERVER/PHILIPS(Release 5.0.9a |January 7, 2002) at 13/05/2003 13:07:24 Content-type: text/plain; charset=us-ascii |------------------------------------------------------------------ |For help or to subscribe/unsubscribe, email majordomo@eda.org |with just the appropriate command message(s) in the body: | | help | subscribe ibis | subscribe ibis-users | unsubscribe ibis | unsubscribe ibis-users | |or email a written request to ibis-request@eda.org. | |IBIS reflector archives exist under: | | http://www.eda.org/pub/ibis/email_archive/ Recent | http://www.eda.org/pub/ibis/users_archive/ Recent | http://www.eda.org/pub/ibis/email/ E-mail since 1993 ------------------------------ Date: Wed, 14 May 2003 17:26:36 +0530 From: "Birendra Rana" Subject: [IBIS-Users] Problem in ibs file generated by s2ibs2 This is a multi-part message in MIME format. - ------_=_NextPart_001_01C31A0F.DEC3524D Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Hi all, =20 I have generated an IBIS Model for an I/O buffer using s2ibis2 script. Interestingly the generated ibs file has entries in the Pull down table as follows : =20 [Pulldown] | voltage I(typ) I(min) I(max) | -1.80 -42.50mA -54.11mA -28.61mA . . . -0.90 -36.68mA -30.62mA -38.74mA -0.90 -36.68mA -30.62mA -38.74mA <- Repetition of above data -0.80 -37.07mA -29.68mA -41.00mA . . . 0.00 0.36uA 2.61nA 2.86uA . . . 3.60 94.05mA 80.81mA 0.11A 0.00 -1.80A 0.11kA -92.95A <- ????? -137.28 -1.70A -99.02A -82.08A <- ????? 3.60 94.05mA 80.81mA 0.11A <- Repetition of 3.60V entry data =20 Similar kind of entries (like the repetition of -0.90V and 3.60V data and extra 2 rows) are there in the Pullup table. The ".out" files however look alright. =20 Any reasons for these extra / repetitive entries ?=20 =20 Regards, =20 Birendra=20 **************************Disclaimer************************************ Information contained in this E-MAIL being proprietary to Wipro Limited is= =20 'privileged' and 'confidential' and intended for use only by the individual or entity to which it is addressed. You are notified that any use, copying= =20 or dissemination of the information contained in the E-MAIL in any manner=20 whatsoever is strictly prohibited. *************************************************************************** - ------_=_NextPart_001_01C31A0F.DEC3524D Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Message

Hi=20 all,

I have=20 generated an IBIS Model for an I/O buffer using s2ibis2 script.= Interestingly=20 the generated ibs file has entries in the Pull down table as=20 follows :

[Pulldown]

| =20 voltage =20 I(typ) = I(min) =20 =20 I(max)

=20 -1.80 &nbs= p;=20 - -42.50mA =20 - -54.11mA =20 - -28.61mA

= .

=20 - -0.90 -36.68mA &n= bsp; =20 - -30.62mA = -38.74mA

=20 - -0.90 -36.68mA &n= bsp; =20 - -30.62mA -38.74mA <-=20 Repetition of above data

=20 - -0.80 =20 - -37.07mA =20 - -29.68mA = -41.00mA

= .

=20 0.00 = ;=20 0.36uA =20 2.61nA =20 2.86uA

= .

=20 3.60 =20 94.05mA =20 80.81mA =20 0.11A

=20 0.00 = ;=20 - -1.80A =20 0.11kA = -92.95A =20 <- ?????

-137.28 &nbs= p; =20 - -1.70A -99.02A &n= bsp; =20 - -82.08A <- ?????

=20 3.60 =20 94.05mA =20 80.81mA =20 0.11A <- Repetition of 3.60V entry=20 data

Similar=20 kind of entries (like the repetition of -0.90V and 3.60V data and extra 2= rows)=20 are there in the Pullup table. The ".out" files however look=20 alright.

Any reasons for these extra /= repetitive=20 entries ?

Regards,

Birendra

**************************Disclaimer***********************=
*************

Information contained in this E-MAIL being proprietary to Wipro Limited is=
=20
'privileged' and 'confidential' and intended for use only by the individual
 or entity to which it is addressed. You are notified that any use, copying=
=20
or dissemination of the information contained in the E-MAIL in any manner=20
whatsoever is strictly prohibited.

***************************************************************************

- ------_=_NextPart_001_01C31A0F.DEC3524D-- |------------------------------------------------------------------ |For help or to subscribe/unsubscribe, email majordomo@eda.org |with just the appropriate command message(s) in the body: | | help | subscribe ibis | subscribe ibis-users | unsubscribe ibis | unsubscribe ibis-users | |or email a written request to ibis-request@eda.org. | |IBIS reflector archives exist under: | | http://www.eda.org/pub/ibis/email_archive/ Recent | http://www.eda.org/pub/ibis/users_archive/ Recent | http://www.eda.org/pub/ibis/email/ E-mail since 1993 ------------------------------ Date: Wed, 14 May 2003 15:24:33 +0200 From: erik.van.der.ven@philips.com Subject: RE: [IBIS-Users] (lv)pecl This is a multipart message in MIME format. - --=_alternative 0049D849C1256D26_= Content-Type: text/plain; charset="us-ascii" Tom, Do you need the netlist as well, or is the plain s2i file good enough for you? (because I cannot send you the spectre file). Birendra seems to have a similar problem. Alex, I am using Spectre for simulations. With kind regards, Erik. Ir. Erik van der Ven Room DB1032 Business Line Networking Infrastructure Philips Semiconductors BV Gerstweg 2 6534 AE Nijmegen The Netherlands Phone: +31-24-3534334 "Tom Dagostino" 05/12/03 05:53 PM Please respond to tom To: Erik van der Ven/NYM/SC/PHILIPS@EMEA2 cc: Subject: RE: [IBIS-Users] (lv)pecl Classification: I've seen some other models with this kind of issue in them from s2ibis. I'm not sure what causes this, it was a while ago and the half life of old problems is relatively short. I would first start by looking at the input file that is generated. Be sure you do not have any typos in it, that the voltages are correct, etc. Send me a copy if you want and I'll take a look at it. Tom Dagostino Teraspeed Consulting Group LLC Teraspeed Consulting Group LLC 2926 SE Yamhill St. Device Modeling Division Portland, OR 97214 13610 SW Harness Lane Beaverton, OR 97008 http://www.teraspeed.com 503-430-1065 tom@teraspeed.com - -----Original Message----- From: owner-ibis-users@server.eda.org [mailto:owner-ibis-users@server.eda.org]On Behalf Of erik.van.der.ven@philips.com Sent: Monday, May 12, 2003 12:37 AM To: ibis-users@server.eda.org Subject: RE: [IBIS-Users] (lv)pecl Tom, About the garbage lines: I use s2ibis for model type output_ECL. Voltage range has been left out (since this created a voltage source of 1.9V to the ground node in the spectre simulation files). Pull-up and pull-down references have been set to 3.3V. The result is an IBIS file that contains a pulldown-curve starting at 1.1V and continuing up to 3.3V. Then the next voltages are: 2.05, 9 times 0V and 3.3V. Most currents are equal to the 3.3V current except for the max current, which is increasing for every line (note that I filled in the typical values for the the min and max cases). The pull-up curve ranges from 0V to 2.2V and is then followed by 10 times 0V and 2.2V. The current for the 0V lines is always 0.000A, except for the first one. So I get some strange values and the range is from 0-2.2V instead of -3.3 to 6.6V. With kind regards, Ir. Erik van der Ven Room DB1032 Business Line Networking Infrastructure Philips Semiconductors BV Gerstweg 2 6534 AE Nijmegen The Netherlands Phone: +31-24-3534334 "Tom Dagostino" 05/09/03 07:11 PM Please respond to tom To: Erik van der Ven/NYM/SC/PHILIPS@EMEA2 cc: Subject: RE: [IBIS-Users] (lv)pecl Classification: Erik In the old days (in the 60s) when Motorola first developed ECL They found that running ECL from 0 to -5.2 volts worked better because the ground planes on boards at the time was cleaner. ECL is referenced to the most positive supply, thus a clean reference was important. In those days the ground could have been a complete plane of the board but power was in many cases distributed via traces on one of the layer. In today's modern circuit boards both the power and ground are distributed in planes so this is not an issue. The voltage difference you see is not important. When you are running the SPICE simulation you just need to connect the Vcc to 3.3 and the Vee to ground to get the PECL model. Remember the 50 Ohm termination needs to be connected to Vcc - 2 volts or 1.3 for the typical case when running the AC simulations. I do have concerns about the table range you are seeing. It should be between -3.3 and +6.6 Volts for all the IV tables. The simulator does several things with the data. First of all it will check the data to ensure it is at least consistent, has not syntax issues, etc. Then, for outputs, it builds a set of coefficients that describes how the buffer transitions from pullup to pulldown and from pulldown to pullup. This table is based on the VT waveforms and the IV curves. The output impedance of the buffer is composed of the sum of the pullup or pulldown IV table plus the power and ground clamps plus the component of C_comp. If the buffer is an input the the power and ground clamps are summed and put in parallel with C_comp. Because the model is designated ECL, the simulator makes one different calculation for the pulldown table than it does for CMOS, see below. What is the 10 lines of garbage you are seeing? Hope that helps. Tom Dagostino Teraspeed Consulting Group LLC Teraspeed Consulting Group LLC 2926 SE Yamhill St. Device Modeling Division Portland, OR 97214 13610 SW Harness Lane Beaverton, OR 97008 http://www.teraspeed.com 503-430-1065 tom@teraspeed.com - -----Original Message----- From: owner-ibis-users@server.eda.org [mailto:owner-ibis-users@server.eda.org]On Behalf Of erik.van.der.ven@philips.com Sent: Friday, May 09, 2003 12:41 AM To: ibis-users@server.eda.org Subject: RE: [IBIS-Users] (lv)pecl Tom, Thank you for your reply. I am starting with a Spectre netlist. I have tried s2ibis to make a model for LVPECL. I noticed some differences. ECL has a supply of 0V (plus) and -5.2V (neg). My circuit has a supply of 3.3V (plus) and 0V (neg). The pulldown table ranges from 1.1V to 3.3V (the pull down reference has been set to 3.3V, the pull-up reference as well), followed by ten lines of garbage. A collegue of mine has changed to pragram a bit so the pull down curve starts at 0V and ends at 2.2V (still followed by ten lines of garbage). Is this a correct range? What does the simulator that uses the IBIS model do with the information that it is an output-ECL model type? And how are the data tables interpreted in conjunction with the ECL_model type? With kind regards, Ir. Erik van der Ven Room DB1032 Business Line Networking Infrastructure Philips Semiconductors BV Gerstweg 2 6534 AE Nijmegen The Netherlands Phone: +31-24-3534334 "Tom Dagostino" 05/08/03 07:16 PM Please respond to tom To: Erik van der Ven/NYM/SC/PHILIPS@EMEA2 cc: Subject: RE: [IBIS-Users] (lv)pecl Classification: Erik What are you starting with? A SPICE description or are you going to make the model from measurements? If you start with SPICE there is a spice to ibis program that you can download from the ibis home page. If you are starting from measurements then you will need a lot of equipment to make the measurements. You will have to manually convert the measurements to the ibis data. Simulators use the output_ecl line to know how to handle ECL. In IBIS ECL models are slightly different than standard CMOS or TTL drivers. In CMOS or TTL the pulldown current is sunk into the ground plane and the pullup current is sourced from the supply. With PECL both the pullup and pulldown are sourced from the supply. So in PECL the pulldown is referenced to the supply, not ground. The simulator needs to know this when it is using the IV tables. Tom Dagostino Teraspeed Consulting Group LLC Teraspeed Consulting Group LLC 2926 SE Yamhill St. Device Modeling Division Portland, OR 97214 13610 SW Harness Lane Beaverton, OR 97008 http://www.teraspeed.com 503-430-1065 tom@teraspeed.com - -----Original Message----- From: owner-ibis-users@server.eda.org [mailto:owner-ibis-users@server.eda.org]On Behalf Of erik.van.der.ven@philips.com Sent: Thursday, May 08, 2003 12:04 AM To: ibis-users@server.eda.org Subject: [IBIS-Users] (lv)pecl Dear all, I think I mailed my question too early since I subscribed to the user group at the same time. So I'll post it again, please see below. Ir. Erik van der Ven Room DB1032 Business Line Networking Infrastructure Philips Semiconductors BV Gerstweg 2 6534 AE Nijmegen The Netherlands Phone: +31-24-3534334 - ----- Forwarded by Erik van der Ven/NYM/SC/PHILIPS on 05/08/03 09:03 AM - ----- Erik van der Ven 05/06/03 02:01 PM To: ibis-users@eda.org cc: Subject: (lv)pecl Classification: Unclassified 1. How can I make an IBIS model of a (LV)PECL model? 2. What does an IBIS simulator do with the model type information (like output_ECL)? Can anyone help me? Thanks. With kind regards, Ir. Erik van der Ven Room DB1032 Business Line Networking Infrastructure Philips Semiconductors BV Gerstweg 2 6534 AE Nijmegen The Netherlands Phone: +31-24-3534334 - --=_alternative 0049D849C1256D26_= Content-Type: text/html; charset="us-ascii"
Tom,

Do you need the netlist as well, or is the plain s2i file good enough for you? (because I cannot send you the spectre file).

Birendra seems to have a similar problem.

Alex,

I am using Spectre for simulations.

With kind regards,
Erik.

Ir. Erik van der Ven
Room DB1032
Business Line Networking Infrastructure
Philips Semiconductors BV
Gerstweg 2
6534 AE Nijmegen
The Netherlands
Phone: +31-24-3534334

"Tom Dagostino" <tom@teraspeed.com>

05/12/03 05:53 PM
Please respond to tom

To: Erik van der Ven/NYM/SC/PHILIPS@EMEA2
cc:
Subject: RE: [IBIS-Users] (lv)pecl

Classification:

I've seen some other models with this kind of issue in them from s2ibis. I'm not sure what causes this, it was a while ago and the half life of old problems is relatively short. I would first start by looking at the input file that is generated. Be sure you do not have any typos in it, that the voltages are correct, etc. Send me a copy if you want and I'll take a look at it.

Tom Dagostino
Teraspeed Consulting Group LLC Teraspeed Consulting Group LLC
2926 SE Yamhill St. Device Modeling Division
Portland, OR 97214 13610 SW Harness Lane
Beaverton, OR 97008
http://www.teraspeed.com 503-430-1065

tom@teraspeed.com
-----Original Message-----
From: owner-ibis-users@server.eda.org [mailto:owner-ibis-users@server.eda.org]On Behalf Of erik.van.der.ven@philips.com
Sent: Monday, May 12, 2003 12:37 AM
To: ibis-users@server.eda.org
Subject: RE: [IBIS-Users] (lv)pecl

Tom,

About the garbage lines:
I use s2ibis for model type output_ECL.
Voltage range has been left out (since this created a voltage source of 1.9V to the ground node in the spectre simulation files).
Pull-up and pull-down references have been set to 3.3V.

The result is an IBIS file that contains a pulldown-curve starting at 1.1V and continuing up to 3.3V.
Then the next voltages are: 2.05, 9 times 0V and 3.3V. Most currents are equal to the 3.3V current except for the max current, which is increasing for every line (note that I filled in the typical values for the the min and max cases).

The pull-up curve ranges from 0V to 2.2V and is then followed by 10 times 0V and 2.2V. The current for the 0V lines is always 0.000A, except for the first one.

So I get some strange values and the range is from 0-2.2V instead of -3.3 to 6.6V.

With kind regards,

Ir. Erik van der Ven
Room DB1032
Business Line Networking Infrastructure
Philips Semiconductors BV
Gerstweg 2
6534 AE Nijmegen
The Netherlands
Phone: +31-24-3534334

"Tom Dagostino" <tom@teraspeed.com>
05/09/03 07:11 PM
Please respond to tom

To: Erik van der Ven/NYM/SC/PHILIPS@EMEA2
cc:
Subject: RE: [IBIS-Users] (lv)pecl
Classification:

Erik

In the old days (in the 60s) when Motorola first developed ECL They found that running ECL from 0 to -5.2 volts worked better because the ground planes on boards at the time was cleaner. ECL is referenced to the most positive supply, thus a clean reference was important. In those days the ground could have been a complete plane of the board but power was in many cases distributed via traces on one of the layer. In today's modern circuit boards both the power and ground are distributed in planes so this is not an issue.

The voltage difference you see is not important. When you are running the SPICE simulation you just need to connect the Vcc to 3.3 and the Vee to ground to get the PECL model. Remember the 50 Ohm termination needs to be connected to Vcc - 2 volts or 1.3 for the typical case when running the AC simulations.

I do have concerns about the table range you are seeing. It should be between -3.3 and +6.6 Volts for all the IV tables.

The simulator does several things with the data. First of all it will check the data to ensure it is at least consistent, has not syntax issues, etc. Then, for outputs, it builds a set of coefficients that describes how the buffer transitions from pullup to pulldown and from pulldown to pullup. This table is based on the VT waveforms and the IV curves.

The output impedance of the buffer is composed of the sum of the pullup or pulldown IV table plus the power and ground clamps plus the component of C_comp.

If the buffer is an input the the power and ground clamps are summed and put in parallel with C_comp.

Because the model is designated ECL, the simulator makes one different calculation for the pulldown table than it does for CMOS, see below.

What is the 10 lines of garbage you are seeing?

Hope that helps.

Tom Dagostino
Teraspeed Consulting Group LLC Teraspeed Consulting Group LLC
2926 SE Yamhill St. Device Modeling Division
Portland, OR 97214 13610 SW Harness Lane
Beaverton, OR 97008
http://www.teraspeed.com 503-430-1065

tom@teraspeed.com
- -----Original Message-----
From: owner-ibis-users@server.eda.org [mailto:owner-ibis-users@server.eda.org]On Behalf Of erik.van.der.ven@philips.com
Sent: Friday, May 09, 2003 12:41 AM
To: ibis-users@server.eda.org
Subject: RE: [IBIS-Users] (lv)pecl

Tom,

Thank you for your reply. I am starting with a Spectre netlist. I have tried s2ibis to make a model for LVPECL.
I noticed some differences. ECL has a supply of 0V (plus) and -5.2V (neg). My circuit has a supply of 3.3V (plus) and 0V (neg).
The pulldown table ranges from 1.1V to 3.3V (the pull down reference has been set to 3.3V, the pull-up reference as well), followed by ten lines of garbage. A collegue of mine has changed to pragram a bit so the pull down curve starts at 0V and ends at 2.2V (still followed by ten lines of garbage).
Is this a correct range?
What does the simulator that uses the IBIS model do with the information that it is an output-ECL model type? And how are the data tables interpreted in conjunction with the ECL_model type?

With kind regards,

Ir. Erik van der Ven
Room DB1032
Business Line Networking Infrastructure
Philips Semiconductors BV
Gerstweg 2
6534 AE Nijmegen
The Netherlands
Phone: +31-24-3534334

"Tom Dagostino" <tom@teraspeed.com>
05/08/03 07:16 PM
Please respond to tom

To: Erik van der Ven/NYM/SC/PHILIPS@EMEA2
cc:
Subject: RE: [IBIS-Users] (lv)pecl
Classification:

Erik

What are you starting with? A SPICE description or are you going to make the model from measurements? If you start with SPICE there is a spice to ibis program that you can download from the ibis home page. If you are starting from measurements then you will need a lot of equipment to make the measurements. You will have to manually convert the measurements to the ibis data.

Simulators use the output_ecl line to know how to handle ECL. In IBIS ECL models are slightly different than standard CMOS or TTL drivers. In CMOS or TTL the pulldown current is sunk into the ground plane and the pullup current is sourced from the supply. With PECL both the pullup and pulldown are sourced from the supply. So in PECL the pulldown is referenced to the supply, not ground. The simulator needs to know this when it is using the IV tables.

Tom Dagostino
Teraspeed Consulting Group LLC Teraspeed Consulting Group LLC
2926 SE Yamhill St. Device Modeling Division
Portland, OR 97214 13610 SW Harness Lane
Beaverton, OR 97008
http://www.teraspeed.com 503-430-1065

1. How can I make an IBIS model of a (LV)PECL model?
2. What does an IBIS simulator do with the model type information (like output_ECL)?

Can anyone help me?
Thanks.

With kind regards,

Ir. Erik van der Ven
Room DB1032
Business Line Networking Infrastructure
Philips Semiconductors BV
Gerstweg 2
6534 AE Nijmegen
The Netherlands
Phone: +31-24-3534334

- --=_alternative 0049D849C1256D26_=-- |------------------------------------------------------------------ |For help or to subscribe/unsubscribe, email majordomo@eda.org |with just the appropriate command message(s) in the body: | | help | subscribe ibis | subscribe ibis-users | unsubscribe ibis | unsubscribe ibis-users | |or email a written request to ibis-request@eda.org. | |IBIS reflector archives exist under: | | http://www.eda.org/pub/ibis/email_archive/ Recent | http://www.eda.org/pub/ibis/users_archive/ Recent | http://www.eda.org/pub/ibis/email/ E-mail since 1993 ------------------------------ Date: Wed, 14 May 2003 16:49:36 +0200 From: "Henrik G. Madsen" Subject: RE: [IBIS-Users] (lv)pecl This is a multi-part message in MIME format. - ------_=_NextPart_001_01C31A28.0A123E3C Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Relating to garbage lines =20 We are using the s2ibis2 (windows version) and having similar problems. = They starts when the supply voltage is reduced below 3.3 V and gets = worse and worse as the supply voltage drops. So the issue is worse for = 1.8 V models than 2.5 V models etc. =20 I brought up the issue around a year ago on the list with no replies. =20 The Spice results files are OK, so the problems relates to the way that = s2ibis2 reads them. The 'workaround' we use it to extract the missing/erronous points from = the simulation files and adding them to the IBIS file manually. =20 Regards /Henrik G Madsen - -----Original Message----- From: erik.van.der.ven@philips.com [mailto:erik.van.der.ven@philips.com] Sent: 14. maj 2003 15:25 To: ibis-users@eda.org Subject: RE: [IBIS-Users] (lv)pecl Tom,=20 Do you need the netlist as well, or is the plain s2i file good enough = for you? (because I cannot send you the spectre file).=20 Birendra seems to have a similar problem.=20 Alex,=20 I am using Spectre for simulations.=20 With kind regards,=20 Erik.=20 Ir. Erik van der Ven Room DB1032 Business Line Networking Infrastructure Philips Semiconductors BV Gerstweg 2 6534 AE Nijmegen The Netherlands Phone: +31-24-3534334=20 =09 "Tom Dagostino" =20 05/12/03 05:53 PM=20 Please respond to tom=20 =20 To: Erik van der Ven/NYM/SC/PHILIPS@EMEA2=20 cc: =20 Subject: RE: [IBIS-Users] (lv)pecl=20 Classification: =20 I've seen some other models with this kind of issue in them from s2ibis. = I'm not sure what causes this, it was a while ago and the half life of = old problems is relatively short. I would first start by looking at the = input file that is generated. Be sure you do not have any typos in it, = that the voltages are correct, etc. Send me a copy if you want and I'll = take a look at it.=20 =20 Tom Dagostino=20 Teraspeed Consulting Group LLC Teraspeed Consulting Group LLC=20 2926 SE Yamhill St. Device Modeling Division=20 Portland, OR 97214 13610 SW Harness Lane=20 Beaverton, OR 97008=20 http://www.teraspeed.com 503-430-1065=20 tom@teraspeed.com=20 - -----Original Message----- From: owner-ibis-users@server.eda.org = [mailto:owner-ibis-users@server.eda.org]On Behalf Of = erik.van.der.ven@philips.com Sent: Monday, May 12, 2003 12:37 AM To: ibis-users@server.eda.org Subject: RE: [IBIS-Users] (lv)pecl Tom,=20 About the garbage lines:=20 I use s2ibis for model type output_ECL.=20 Voltage range has been left out (since this created a voltage source of = 1.9V to the ground node in the spectre simulation files).=20 Pull-up and pull-down references have been set to 3.3V.=20 The result is an IBIS file that contains a pulldown-curve starting at = 1.1V and continuing up to 3.3V.=20 Then the next voltages are: 2.05, 9 times 0V and 3.3V. Most currents are = equal to the 3.3V current except for the max current, which is = increasing for every line (note that I filled in the typical values for = the the min and max cases).=20 The pull-up curve ranges from 0V to 2.2V and is then followed by 10 = times 0V and 2.2V. The current for the 0V lines is always 0.000A, except = for the first one.=20 So I get some strange values and the range is from 0-2.2V instead of = - -3.3 to 6.6V.=20 With kind regards,=20 Ir. Erik van der Ven Room DB1032 Business Line Networking Infrastructure Philips Semiconductors BV Gerstweg 2 6534 AE Nijmegen The Netherlands Phone: +31-24-3534334=20 =09 "Tom Dagostino" =20 05/09/03 07:11 PM=20 Please respond to tom=20 =20 To: Erik van der Ven/NYM/SC/PHILIPS@EMEA2=20 cc: =20 Subject: RE: [IBIS-Users] (lv)pecl=20 Classification: =20 Erik=20 =20 In the old days (in the 60s) when Motorola first developed ECL They = found that running ECL from 0 to -5.2 volts worked better because the = ground planes on boards at the time was cleaner. ECL is referenced to = the most positive supply, thus a clean reference was important. In = those days the ground could have been a complete plane of the board but = power was in many cases distributed via traces on one of the layer. In = today's modern circuit boards both the power and ground are distributed = in planes so this is not an issue. =20 =20 The voltage difference you see is not important. When you are running = the SPICE simulation you just need to connect the Vcc to 3.3 and the Vee = to ground to get the PECL model. Remember the 50 Ohm termination needs = to be connected to Vcc - 2 volts or 1.3 for the typical case when = running the AC simulations.=20 =20 I do have concerns about the table range you are seeing. It should be = between -3.3 and +6.6 Volts for all the IV tables.=20 =20 The simulator does several things with the data. First of all it will = check the data to ensure it is at least consistent, has not syntax = issues, etc. Then, for outputs, it builds a set of coefficients that = describes how the buffer transitions from pullup to pulldown and from = pulldown to pullup. This table is based on the VT waveforms and the IV = curves.=20 =20 The output impedance of the buffer is composed of the sum of the pullup = or pulldown IV table plus the power and ground clamps plus the component = of C_comp.=20 =20 If the buffer is an input the the power and ground clamps are summed and = put in parallel with C_comp.=20 =20 Because the model is designated ECL, the simulator makes one different = calculation for the pulldown table than it does for CMOS, see below.=20 =20 What is the 10 lines of garbage you are seeing?=20 =20 Hope that helps.=20 =20 Tom Dagostino=20 Teraspeed Consulting Group LLC Teraspeed Consulting Group LLC=20 2926 SE Yamhill St. Device Modeling Division=20 Portland, OR 97214 13610 SW Harness Lane=20 Beaverton, OR 97008=20 http://www.teraspeed.com 503-430-1065=20 tom@teraspeed.com=20 - -----Original Message----- From: owner-ibis-users@server.eda.org = [mailto:owner-ibis-users@server.eda.org]On Behalf Of = erik.van.der.ven@philips.com Sent: Friday, May 09, 2003 12:41 AM To: ibis-users@server.eda.org Subject: RE: [IBIS-Users] (lv)pecl Tom,=20 Thank you for your reply. I am starting with a Spectre netlist. I have = tried s2ibis to make a model for LVPECL.=20 I noticed some differences. ECL has a supply of 0V (plus) and -5.2V = (neg). My circuit has a supply of 3.3V (plus) and 0V (neg).=20 The pulldown table ranges from 1.1V to 3.3V (the pull down reference has = been set to 3.3V, the pull-up reference as well), followed by ten lines = of garbage. A collegue of mine has changed to pragram a bit so the pull = down curve starts at 0V and ends at 2.2V (still followed by ten lines of = garbage).=20 Is this a correct range?=20 What does the simulator that uses the IBIS model do with the information = that it is an output-ECL model type? And how are the data tables = interpreted in conjunction with the ECL_model type?=20 With kind regards,=20 Ir. Erik van der Ven Room DB1032 Business Line Networking Infrastructure=20 Philips Semiconductors BV Gerstweg 2 6534 AE Nijmegen The Netherlands Phone: +31-24-3534334=20 =09 "Tom Dagostino" =20 05/08/03 07:16 PM=20 Please respond to tom=20 =20 To: Erik van der Ven/NYM/SC/PHILIPS@EMEA2=20 cc: =20 Subject: RE: [IBIS-Users] (lv)pecl=20 Classification: =20 Erik=20 What are you starting with? A SPICE description or are you going to = make the model from measurements? If you start with SPICE there is a = spice to ibis program that you can download from the ibis home page. If = you are starting from measurements then you will need a lot of equipment = to make the measurements. You will have to manually convert the = measurements to the ibis data.=20 Simulators use the output_ecl line to know how to handle ECL. In IBIS = ECL models are slightly different than standard CMOS or TTL drivers. In = CMOS or TTL the pulldown current is sunk into the ground plane and the = pullup current is sourced from the supply. With PECL both the pullup = and pulldown are sourced from the supply. So in PECL the pulldown is = referenced to the supply, not ground. The simulator needs to know this = when it is using the IV tables.=20 Tom Dagostino=20 Teraspeed Consulting Group LLC Teraspeed Consulting Group LLC=20 2926 SE Yamhill St. Device Modeling Division=20 Portland, OR 97214 13610 SW Harness Lane=20 Beaverton, OR 97008=20 http://www.teraspeed.com 503-430-1065=20 tom@teraspeed.com=20 - -----Original Message----- From: owner-ibis-users@server.eda.org = [mailto:owner-ibis-users@server.eda.org]On Behalf Of = erik.van.der.ven@philips.com Sent: Thursday, May 08, 2003 12:04 AM To: ibis-users@server.eda.org Subject: [IBIS-Users] (lv)pecl Dear all,=20 I think I mailed my question too early since I subscribed to the user = group at the same time. So I'll post it again, please see below.=20 Ir. Erik van der Ven Room DB1032 Business Line Networking Infrastructure Philips Semiconductors BV Gerstweg 2 6534 AE Nijmegen The Netherlands Phone: +31-24-3534334=20 - ----- Forwarded by Erik van der Ven/NYM/SC/PHILIPS on 05/08/03 09:03 AM = - -----=20 =09 Erik van der Ven=20 05/06/03 02:01 PM=20 =20 To: ibis-users@eda.org=20 cc: =20 Subject: (lv)pecl=20 Classification: Unclassified=20 1. How can I make an IBIS model of a (LV)PECL model?=20 2. What does an IBIS simulator do with the model type information (like = output_ECL)?=20 Can anyone help me?=20 Thanks.=20 With kind regards,=20 Ir. Erik van der Ven Room DB1032 Business Line Networking Infrastructure Philips Semiconductors BV Gerstweg 2 6534 AE Nijmegen The Netherlands Phone: +31-24-3534334=20 - ------_=_NextPart_001_01C31A28.0A123E3C Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Relating to garbage lines

We are=20 using the s2ibis2 (windows version) and having similar problems. They = starts=20 when the supply voltage is reduced below 3.3 V and gets worse and worse = as the=20 supply voltage drops. So the issue is worse for 1.8 V models than 2.5 V = models=20 etc.

I=20 brought up the issue around a year ago on the list with no=20 replies.

The=20 Spice results files are OK, so the problems relates to the way that = s2ibis2=20 reads them.

The=20 'workaround' we use it to extract the missing/erronous points from the=20 simulation files and adding them to the IBIS file = manually.

Regards

/Henrik G Madsen

-----Original Message-----
From: = erik.van.der.ven@philips.com=20 [mailto:erik.van.der.ven@philips.com]
Sent: 14. maj 2003=20 15:25
To: ibis-users@eda.org
Subject: RE: = [IBIS-Users]=20 (lv)pecl

Tom,=20

Do you need the netlist = as well, or=20 is the plain s2i file good enough for you? (because I cannot send you = the=20 spectre file).

Birendra = seems to=20 have a similar problem.

Alex,

I am = using Spectre for=20 simulations.

With = kind=20 regards,
Erik. =

Ir. Erik van der Ven
Room = DB1032
Business Line=20 Networking Infrastructure
Philips Semiconductors BV
Gerstweg = 2
6534 AE=20 Nijmegen
The Netherlands
Phone: +31-24-3534334

"Tom = Dagostino"=20 <tom@teraspeed.com>=20

05/12/03 05:53 PM =
Please respond to tom

=
To: = =20 Erik van der Ven/NYM/SC/PHILIPS@EMEA2 =
cc: = =20
= =20 Subject: RE: [IBIS-Users]=20 (lv)pecl=20

=20 Classification: =20

I've=20 seen some other models with this kind of issue in them from s2ibis. = I'm=20 not sure what causes this, it was a while ago and the half life of old = problems=20 is relatively short. I would first start by looking at the input = file that=20 is generated. Be sure you do not have any typos in it, that the = voltages=20 are correct, etc. Send me a copy if you want and I'll take a look = at=20 it.
=
Tom Dagostino
Teraspeed Consulting Group LLC Teraspeed = Consulting Group=20 LLC
2926 SE Yamhill St. = =20 Device Modeling Division =
Portland, OR 97214 = =20 13610 SW Harness Lane =
= =20 =20 Beaverton, OR 97008
http://www.teraspeed.com = 503-430-1065=20

tom@teraspeed.com
-----Original=20 Message-----
From: owner-ibis-users@server.eda.org=20 [mailto:owner-ibis-users@server.eda.org]On Behalf Of=20 erik.van.der.ven@philips.com
Sent: Monday, May 12, 2003 = 12:37=20 AM
To: ibis-users@server.eda.org
Subject: RE: = [IBIS-Users]=20 (lv)pecl

Tom, =

About=20 the garbage lines: =
I use s2ibis for model type = output_ECL.
Voltage=20 range has been left out (since this created a voltage source of = 1.9V to=20 the ground node in the spectre simulation files).
Pull-up=20 and pull-down references have been set to 3.3V.

The=20 result is an IBIS file that contains a pulldown-curve starting at 1.1V = and=20 continuing up to 3.3V. =
Then the next voltages are: 2.05, 9 times = 0V and=20 3.3V. Most currents are equal to the 3.3V current except for the max = current,=20 which is increasing for every line (note that I filled in the typical = values for=20 the the min and max cases).=20

The pull-up curve ranges = from 0V to=20 2.2V and is then followed by 10 times 0V and 2.2V. The current for the = 0V lines=20 is always 0.000A, except for the first one.

So I get some = strange values=20 and the range is from 0-2.2V instead of -3.3 to 6.6V.

With=20 kind regards, =

Ir. Erik van der Ven
Room = DB1032
Business=20 Line Networking Infrastructure
Philips Semiconductors BV
Gerstweg=20 2
6534 AE Nijmegen
The Netherlands
Phone: = +31-24-3534334

"Tom=20 Dagostino" <tom@teraspeed.com>
05/09/03 07:11 PM
Please respond to tom
= =20
= To:=20 Erik van der=20 Ven/NYM/SC/PHILIPS@EMEA2=20
= cc:=20 =20
=20 Subject: RE: [IBIS-Users]=20 (lv)pecl
=20 Classification: =

Erik=20

In the old = days (in the=20 60s) when Motorola first developed ECL They found that running ECL from = 0 to=20 - -5.2 volts worked better because the ground planes on boards at the time = was=20 cleaner. ECL is referenced to the most positive supply, thus a = clean=20 reference was important. In those days the ground could have been = a=20 complete plane of the board but power was in many cases distributed via = traces=20 on one of the layer. In today's modern circuit boards both the = power and=20 ground are distributed in planes so this is not an issue. =

The voltage difference you see is not important. When = you are=20 running the SPICE simulation you just need to connect the Vcc to 3.3 and = the Vee=20 to ground to get the PECL model. Remember the 50 Ohm termination = needs to=20 be connected to Vcc - 2 volts or 1.3 for the typical case when running = the AC=20 simulations. =

I do have concerns about the = table range you=20 are seeing. It should be between -3.3 and +6.6 Volts for all the = IV=20 tables. =

The simulator does several things = with the=20 data. First of all it will check the data to ensure it is at least = consistent, has not syntax issues, etc. Then, for outputs, it = builds a set=20 of coefficients that describes how the buffer transitions from pullup to = pulldown and from pulldown to pullup. This table is based on the = VT=20 waveforms and the IV curves.=20

The output = impedance of=20 the buffer is composed of the sum of the pullup or pulldown IV table = plus the=20 power and ground clamps plus the component of C_comp.

If the buffer is an input the the power and ground clamps = are summed=20 and put in parallel with C_comp.=20

Because = the model is=20 designated ECL, the simulator makes one different calculation for the = pulldown=20 table than it does for CMOS, see below.

What is the 10=20 lines of garbage you are seeing?=20

Hope that=20 helps. =

Tom Dagostino
Teraspeed = Consulting Group=20 LLC Teraspeed Consulting Group LLC
2926=20 SE Yamhill St. = Device=20 Modeling Division =
Portland, OR 97214 = =20 13610 SW Harness Lane
=20 = =20 Beaverton, OR 97008
http://www.teraspeed.com = 503-430-1065

tom@teraspeed.com
-----Original=20 Message-----
From: owner-ibis-users@server.eda.org=20 [mailto:owner-ibis-users@server.eda.org]On Behalf Of=20 erik.van.der.ven@philips.com
Sent: Friday, May 09, 2003 = 12:41=20 AM
To: ibis-users@server.eda.org
Subject: RE: = [IBIS-Users]=20 (lv)pecl

Tom,=20

Thank you for your = reply. I am=20 starting with a Spectre netlist. I have tried s2ibis to make a model for = LVPECL.
I noticed some differences. ECL has a supply of 0V (plus) = and -5.2V=20 (neg). My circuit has a supply of 3.3V (plus) and 0V (neg).
The=20 pulldown table ranges from 1.1V to 3.3V (the pull down reference has = been set to=20 3.3V, the pull-up reference as well), followed by ten lines of garbage. = A=20 collegue of mine has changed to pragram a bit so the pull down curve = starts at=20 0V and ends at 2.2V (still followed by ten lines of = garbage).
Is this a=20 correct range? =
What does the simulator that uses the = IBIS model do=20 with the information that it is an output-ECL model type? And how are = the data=20 tables interpreted in conjunction with the ECL_model type?

With=20 kind regards, =

Ir. Erik van der Ven
Room = DB1032
Business=20 Line Networking Infrastructure=20
Philips Semiconductors = BV
Gerstweg=20 2
6534 AE Nijmegen
The Netherlands
Phone: = +31-24-3534334

"Tom=20 Dagostino" <tom@teraspeed.com>
05/08/03 07:16 PM
Please respond to tom
= =20
= To: =20 Erik van der = Ven/NYM/SC/PHILIPS@EMEA2
cc: =20
Subject: = =20 RE: [IBIS-Users] (lv)pecl
=20 Classification: =

Erik =

What are you starting with? = A SPICE=20 description or are you going to make the model from measurements? = If you=20 start with SPICE there is a spice to ibis program that you can download = from the=20 ibis home page. If you are starting from measurements then you = will need a=20 lot of equipment to make the measurements. You will have to = manually=20 convert the measurements to the ibis data.

Simulators use the=20 output_ecl line to know how to handle ECL. In IBIS ECL models are = slightly=20 different than standard CMOS or TTL drivers. In CMOS or TTL the = pulldown=20 current is sunk into the ground plane and the pullup current is sourced = from the=20 supply. With PECL both the pullup and pulldown are sourced from = the=20 supply. So in PECL the pulldown is referenced to the supply, not = ground.=20 The simulator needs to know this when it is using the IV=20 tables.

Tom Dagostino
Teraspeed = Consulting Group=20 LLC Teraspeed Consulting Group LLC
2926=20 SE Yamhill St. = Device=20 Modeling Division =
Portland, OR 97214 = =20 13610 SW Harness Lane
=20 = =20 Beaverton, OR 97008
http://www.teraspeed.com = 503-430-1065

1. How can I make an IBIS = model of a=20 (LV)PECL model? =
2. What does an IBIS simulator do with = the model type=20 information (like output_ECL)?=20

Can anyone help = me?
Thanks. =

With kind regards,

Ir.=20 Erik van der Ven
Room DB1032
Business Line Networking=20 Infrastructure
Philips Semiconductors BV
Gerstweg 2
6534 AE=20 Nijmegen
The Netherlands
Phone: +31-24-3534334

- ------_=_NextPart_001_01C31A28.0A123E3C-- |------------------------------------------------------------------ |For help or to subscribe/unsubscribe, email majordomo@eda.org |with just the appropriate command message(s) in the body: | | help | subscribe ibis | subscribe ibis-users | unsubscribe ibis | unsubscribe ibis-users | |or email a written request to ibis-request@eda.org. | |IBIS reflector archives exist under: | | http://www.eda.org/pub/ibis/email_archive/ Recent | http://www.eda.org/pub/ibis/users_archive/ Recent | http://www.eda.org/pub/ibis/email/ E-mail since 1993 ------------------------------ End of ibis-users V1 #23 ************************