RE: [IBIS-Users] Question about C_comp and [C Comp Corner]

Hello Kazunori Yamada,

 

[C Comp Corner] is a newer keyword in IBIS to provide

C_comp information that overrides any existing C_comp

information directly positioned under the [Model] keyword.

 

The information under [C Comp Corner] is intended to be

directly correlated with the other [Model] typ/min/max

column information, as would be extracted under the

same process/voltage/temperature conditions.  Because

of this, the EDA tool is expected to use the same C_comp

column information with the [Model] corner information.

For example, the C_comp min column information would be

used only with the [Model] min column information.

 

Also, [C Comp Corner] example shows that the entries are

not necessarily positioned by magnitude.  For example,

the min column entries are larger than the max column

entries.

 

With the original C_comp information positioned under the

[Model] keyword, the column entries are positioned by

magnitude (smallest value under the min column, etc.) to

provide the typ and max and min values to be used.

The EDA tool is expected to allow the user to select any or

all of the C_comp corner values to test a range of solutions

that may exist for different pins.  (Also the original reason

for this approach was that the on-die interconnect portion

extracted as part of C_comp might be different for each pin.)

 

Best Regards,

Bob

 

 

 

From: owner-ibis-users@eda.org [mailto:owner-ibis-users@eda.org] On Behalf
Of KAZUNORI YAMADA
Sent: Wednesday, March 04, 2015 6:18 PM
To: ibis-users@eda.org
Subject: [IBIS-Users] Question about C_comp and [C Comp Corner]

 

Hi experts.

 

I have a question about C_comp and [C Comp Corner].

 

In the version 5.1 and later,

I can describe the C_comp* by corners under [Model].

[Model]

C_comp 7.0pF 5.0pF 9.0pF 

C_comp_pullup 3.0pF 2.5pF 3.5pF | These four can be 

C_comp_pulldown 2.0pF 1.5pF 2.5pF | used instead of 

C_comp_power_clamp 1.0pF 0.5pF 1.5pF | C_comp 

C_comp_gnd_clamp 1.0pF 0.5pF 1.5pF

 

Moreover I can describe the C_comp* by corners under [C Comp Corner].

[C Comp Corner] 

| variable typ min max 

C_comp 7.0pF 9.0pF 5.0pF 

| 

C_comp_pullup 3.0pF 3.5pF 2.5pF | These four can be 

C_comp_pulldown 2.0pF 2.5pF 1.5pF | used instead of 

C_comp_power_clamp 1.0pF 1.5pF 0.5pF | C_comp 

C_comp_gnd_clamp 1.0pF 1.5pF 0.5pF 

|

 

What is different by both of them?

Is the [C Comp Corner] insignificant already?

 

 

best regaeds.

 

Kazunori Yamada.

Renesas System Design Corp.


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