From owner-ibis Wed Apr 10 17:04:04 1996 Received: from gatekeeper.nsc.com (gatekeeper.nsc.com [139.187.71.2]) by vhdl.vhdl.org (8.7.3/8.7.3) with SMTP id RAA03394 for ; Wed, 10 Apr 1996 17:04:03 -0700 (PDT) Received: from nsc.nsc.com by gatekeeper.nsc.com (5.65/fma-120691) with SMTP; id AA09068 for ibis-users@vhdl.org; Wed, 10 Apr 96 16:55:10 -0700 Received: from lightning-gw.nsc.com by nsc.nsc.com (5.65/1.34) with SMTP id AA11262 for ibis-users@vhdl.org; Wed, 10 Apr 96 16:55:09 -0700 Received: from kural by rockie.nsc.com (4.1/SMI-4.1) id AA18632; Wed, 10 Apr 96 16:57:35 PDT Date: Wed, 10 Apr 96 16:57:35 PDT From: huq@rockie.nsc.com (Syed Huq) Message-Id: <9604102357.AA18632@rockie.nsc.com> To: ibis-users@vhdl.org Subject: Ramp rate and Rising/Falling waveform IBISgurus: Ramp rate has been defined to be measured WITHOUT package information. Rising/Falling waveform has been defined to include the pkg and fixture information seperately. I think Ramp rate should have the same options as Rising/Falling, ie. the ability to add pkg and fixture parameters. This will allow an easy way to measure Ramp rate WITH a packaged unit and not on a 'bare die' ! I also wonder what inaccuracies I can expect if I provide Ramp rate data on a packaged unit instead of a bare die. Regards, Syed National Semiconductor From owner-ibis Thu Apr 18 03:37:55 1996 Received: from alcatel.fr (mail.alcatel.fr [193.104.30.131]) by vhdl.vhdl.org (8.7.3/8.7.3) with ESMTP id DAA02746 for ; Thu, 18 Apr 1996 03:37:52 -0700 (PDT) Received: from alcatel.fr (gatekeeper-ssn.alcatel.fr [155.132.180.241]) by mailgate.alcatel.fr (8.7.3/8.7.3) with ESMTP id MAA28516 for ; Thu, 18 Apr 1996 12:28:01 +0200 Received: from ln.cit.alcatel.fr (las40304.ln.cit.alcatel.fr [155.132.225.2]) by nsfhh5.alcatel.fr (8.7.3/8.7.3) with SMTP id MAA25527 for ; Thu, 18 Apr 1996 12:28:21 +0200 (METDST) Received: from las41247.ln.cit.alcatel.fr by ln.cit.alcatel.fr (4.1/SMI-4.1) id AA02306; Thu, 18 Apr 96 12:31:10 +0200 Received: from las41247 (localhost) by las41247.ln.cit.alcatel.fr (4.1/SMI-4.1) id AA01134; Thu, 18 Apr 96 12:31:09 +0200 Sender: fitzpat1@ln.cit.alcatel.fr Message-Id: <317619EC.15FB7483@ln.cit.alcatel.fr> Date: Thu, 18 Apr 1996 12:31:08 +0200 From: FITZPATRICK John Organization: Alcatel CIT, 22304 Lannion, France X-Mailer: Mozilla 2.0 (X11; I; SunOS 4.1.3_U1 sun4c) Mime-Version: 1.0 To: ibis-users@vhdl.org Subject: Switched clamping diodes & input I/V curves with hysteresis Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Hello all, Yesterday, I discussed IBIS with one of our standard logic suppliers. They provide good Spice support, but are only beginning to get interested in behavioural models. Two issues were raised, summarized here for your information: 1) One family of components has a static input I/V characteristics which show a hysteresis effect: the response for a 0->1 transition is not the same as for a 1->0 transition, due to the design of a bus-hold circuit. My view is that IBIS doesn't allow this effect to be modelled. 2) One family of components switches out the power clamp diode whenever the output buffer is in tri-state. My view is that IBIS can model this buffer if the clamping diode characteristics are put in the [Pullup] table and the high-impedance characteristics in the [POWER Clamp] table. However, is there is a potential risk because the simulator will assume that the high-impedance characteristic is constantly present, which is not the case? The risk is serious only if the high-impedance state is not so high (not the case for the logic family under discussion) (There were some concerns also re internal feedback structures, but the actual problems were not very clear to me.) Any comments? John -- John Fitzpatrick Alcatel CIT, 4 rue de Broglie, 22304 Lannion, France Tel: (+33)96.04.79.33 Fax: (+33)96.04.85.09 From owner-ibis Thu Apr 18 05:51:10 1996 Received: from eagle.ColumbiaSC.NCR.COM ([153.78.178.8]) by vhdl.vhdl.org (8.7.3/8.7.3) with SMTP id FAA10293 for ; Thu, 18 Apr 1996 05:51:09 -0700 (PDT) From: mellitz@eagle.ColumbiaSC.NCR.COM >From: mellitz@eagle (Richard.Mellitz) Content-Type: text Message-Id: <9604180844.ZM12902@eagle> Date: Thu, 18 Apr 1996 08:44:35 -0400 In-Reply-To: ln.cit.alcatel.fr!John.Fitzpatrick (FITZPATRICK John) "Switched clamping diodes & input I/V curves with hysteresis" (Apr 18, 12:31pm) References: <317619EC.15FB7483@ln.cit.alcatel.fr> X-Mailer: Z-Mail (2.1.4 02apr93) To: John.Fitzpatrick@ln.cit.alcatel.fr (FITZPATRICK John), ibis-users@vhdl.org Subject: Re: Switched clamping diodes & input I/V curves with hysteresis All, I'd like to add to the list. I've recently encounter quite a few devices that have basically 2 I-V curves. One for switching and one a few nanoseconds later. I think this was discussed a while back but I can't remember the outcome. Richard Mellitz, NCR On Apr 18, 12:31pm, FITZPATRICK John wrote: > Subject: Switched clamping diodes & input I/V curves with hysteresis > Hello all, > > Yesterday, I discussed IBIS with one of our standard logic suppliers. > They provide good Spice support, but are only beginning to get > interested in behavioural models. > > Two issues were raised, summarized here for your information: > > 1) One family of components has a static input I/V characteristics > which show a hysteresis effect: the response for a 0->1 transition > is not the same as for a 1->0 transition, due to the design of > a bus-hold circuit. > > My view is that IBIS doesn't allow this effect to be modelled. > > > 2) One family of components switches out the power clamp > diode whenever the output buffer is in tri-state. > > My view is that IBIS can model this buffer if the clamping diode > characteristics are put in the [Pullup] table and the high-impedance > characteristics in the [POWER Clamp] table. > > However, is there is a potential risk because the simulator > will assume that the high-impedance characteristic is > constantly present, which is not the case? The risk is serious > only if the high-impedance state is not so high (not the > case for the logic family under discussion) > > > (There were some concerns also re internal feedback structures, > but the actual problems were not very clear to me.) > > Any comments? > > John > > > -- > John Fitzpatrick > Alcatel CIT, 4 rue de Broglie, 22304 Lannion, France > Tel: (+33)96.04.79.33 Fax: (+33)96.04.85.09 >-- End of excerpt from FITZPATRICK John