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Forums > Silicon-package-board > Signal Integrity and Modeling

Subject: How to manage die capacitance in a stacked device in IBIS model?
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Saad
Posts: 39
Online: User is Offline
5/18/2006 1:58 AM  
Hello everybody,

I've a stacked (4x die) IBIS model for my device. During the operation one device is active at a time. Each die has a different capacitance (c_comp) however R_pkg, L_pkg & C_pkg should be the same. 

How will I set c_comp in the IBIS model as it is a variable parameter?

Thanks,
Saad.
aaront
Posts: 1
Online: User is Offline
5/22/2006 12:09 PM  
Using the IBIS keyword [Model Selector] might do the trick for you.


[Pin]  signal_name   model_name   R_pin   L_pin    C_pin
|
A1     IO1                 StackIO          
...

[Model Selector]  StackIO
Die1_IO                  IO for first die
Die2_IO                  IO for second die
Die3_IO                  IO for third die
Die4_IO                  IO for fourth die
...

[Model]        Die1_IO
Model_type     I/O
|
Vinl = 650.000mV
Vinh = 1.150V
Vmeas = 900.000mV
Vref = 900.000mV
Cref = 0.0pF
Rref = 25.000Ohm
|
|                            typ                 min                 max
|
C_comp                      2.690pF             2.290pF             3.070pF
|
...

Then from Sigxp you could select which buffer to use in the simulation.
Kalevi2
Moderator
Posts: 69
Online: User is Offline
5/23/2006 4:11 AM  
Aaront's approach or something similar is the only way to go. In SigXP, you can chose the buffer easily. If you want to run lists of nets in probe, you have to run several batch jobs using the different model cases.
Kai Keskinen
Saad
Posts: 39
Online: User is Offline
5/23/2006 5:19 AM  
thanks Aaront, thanks Kai for your help!
Regards Saad.
Donald Telian
Posts: 42
Online: User is Offline
6/13/2006 1:09 PM  
Clever trick for swapping drivers, but it seems you should also 4x C_comp too?
Donald Telian
SI Consultant
telian@sti.net
559-760-5793
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Forums > Silicon-package-board > Signal Integrity and Modeling > How to manage die capacitance in a stacked device in IBIS model?


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