Hi Prabhat: Below is the picture for reference. | | Table Current | ------> | + Table Voltage - | Pin 1 |---------| Pin 2 | <---+ +---> | |---------| | | C_comp values are ignored for [Series Current] models. |----------------------------------------------------------------------------- [Series Current] | Voltage I(typ) I(min) I(max) -5.0V -3900.0m -3800.0m -4000.0m -0.7V -80.0m -75.0m -85.0m -0.6V -22.0m -20.0m -25.0m -0.5V -2.4m -2.0m -2.9m -0.4V 0.0m 0.0m 0.0m 5.0V 0.0m 0.0m 0.0m | The voltage table convention defines the drop from Pin 1 to Pin 2. So a negative table voltage means that the voltage at Pin 2 is higher than Pin 1. The current flow convention might be restated that the current flowing into Pin 1 (and through the series element to Pin 2) is positive. That is consistent with the current flow convention for other keywords and for SPICE. The example represents a series diode whose on state is when the Pin 2 voltage is greater than Pin 1 voltage, and whose off state is just the opposite. So I think the signs are correct. Also, as previously indicated, you probably need to extend the series current voltage table to both the plus and minus voltage directions. That should avoid ambiguity regarding how tools might handle currents for voltage drops that are not specified in the table. Bob Prabhat RANJAN wrote: > Hello Mike n Experts, > > > > Regarding the direction of current, you have mentioned that ? currents > into pin 2 would be negative. It should not be necessary??. > > > > For which condition, above convention would not be valid?? > > > > > > Also, For any positive voltage in V-I table of [Series Current] ( i.e., > voltage of pin 1 is greater than pin2 ) , current will come out from pin > 1 and will go into pin 2 and from Defined convention of [Series > keyword], sign of current will be negative. > > Similarly, for negative voltage, current will be positive. > > > > But, example given under keyword [Series Current] in IBIS ver5.0 > specification document shows negative current for negative voltage. > > > > > > Am I interpreting the ?current direction convention? wrongly or there is > some discrepancy in SPECIFICATION document?? > > > > > > Regards > > > > PRABHAT > > > > > > From: owner-ibis@server.eda.org [mailto:owner-ibis@server.eda.org] On > Behalf Of Mike LaBonte (milabont) > Sent: Monday, September 14, 2009 6:32 PM > To: Edward Rose; ibis-users@server.eda.org; ibis@server.eda.org > Subject: [IBIS] RE: [IBIS-Users] Usage of [Series Current] > > > > The series models below do appear to be equivalent. Voltage on series > models is measured from pin 1 to pin 2 of the [Series Pin Mapping] > entry, and currents into pin 2 would be negative. It should not be > necessary, but it may help to extend the table voltage range all the way > from -1.2V to +2.4V. > > > > In my opinion it is quite likely that there could be issues with some > [Series Current] implementations, and the various tools may behave > differently. If you are an IC vendor you could submit your IBIS file to > the free model review service, where it will be examined and tested by > EDA tool vendors and other experts. > > > > http://www.eigroup.org/ibis/support.htm > > > > Or you could report the problem to the vendor you are using. > > > > Mike > > > > ------------------------------------------------------------------------ > > From: owner-ibis-users@server.eda.org > [mailto:owner-ibis-users@server.eda.org] On Behalf Of Edward Rose > Sent: Monday, September 14, 2009 6:27 AM > To: ibis-users@server.eda.org; ibis@server.eda.org > Subject: [IBIS-Users] Usage of [Series Current] > > Hello Experts, > > > > I am trying to use [Series Current] keyword instead of [R series] in a > Series model as given below. > > > > > > |********************************************************************** > > [Model] SER_RES > Model_type Series > Polarity Non-Inverting > Enable Active-High > C_comp 0pF 0pF 0pF > | > | typ min max > [Voltage Range] 1.2V 1.08V 1.32V > | > | variable R(typ) R(min) R(max) > | > > |[R Series] 100ohm NA NA > | > [End] > > |********************************************************************** > > | > [Model] SER_CURR > > Model_type Series > Polarity Non-Inverting > |Enable Active-High > C_comp 0pF 0pF 0pF > | > | typ min max > [Voltage Range] 1.2V 1.08V 1.32V > | > [Series Current] > | Voltage I(typ) I(min) I(max) > 0.00V 0.0A NA NA > 0.10V -1.0mA NA NA > 0.20V -2.0mA NA NA > 0.30V -3.0mA NA NA > 0.40V -4.0mA NA NA > 0.50V -5.0mA NA NA > 0.60V -6.0mA NA NA > 0.70V -7.0mA NA NA > 0.80V -8.0mA NA NA > 0.90V -9.0mA NA NA > 1.00V -10.0mA NA NA > 1.10V -11.0mA NA NA > 1.20V -12.0mA NA NA > | > [End] > |***************************************************** > > > > According to understanding from IBIS specification document, both above > given models should be identical. > > But, during simulation I am getting different results. > > Series model with only [R series] is giving desirable result while model > with only [Series current] giving totally different results > > > > Am I doing something wrong or there is some problem with my simulator??? > > > > Thanks in advance > > Edward > > > > > > > > > -- > This message has been scanned for viruses and > dangerous content by MailScanner <http://www.mailscanner.info/>, and is > believed to be clean. > > > -- > This message has been scanned for viruses and > dangerous content by MailScanner <http://www.mailscanner.info/>, and is > believed to be clean. > > > -- > This message has been scanned for viruses and > dangerous content by MailScanner <http://www.mailscanner.info/>, and is > believed to be clean. -- Bob Ross Teraspeed Consulting Group LLC Teraspeed Labs 121 North River Drive 13610 SW Harness Lane Narragansett, RI 02882 Beaverton, OR 97008 401-284-1827 503-430-1065 http://www.teraspeed.com 503-246-8048 Direct bob@teraspeed.com Teraspeed is a registered service mark of Teraspeed Consulting Group LLC -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. -------------------------------------------------------------------- |For help or to subscribe/unsubscribe, e-mail majordomo@eda-stds.org |with the appropriate command message(s) in the body: | | help | subscribe ibis <optional e-mail address, if different> | subscribe ibis-users <optional e-mail address, if different> | unsubscribe ibis <optional e-mail address, if different> | unsubscribe ibis-users <optional e-mail address, if different> | |or e-mail a request to ibis-request@eda-stds.org. | |IBIS reflector archives exist under: | | http://www.eda-stds.org/pub/ibis/email_archive/ Recent | http://www.eda-stds.org/pub/ibis/users_archive/ Recent | http://www.eda-stds.org/pub/ibis/email/ E-mail since 1993Received on Wed Sep 23 18:09:52 2009
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