RE: [IBIS-Users] Usage of [Series Current]

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

 

 

 


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