Open-drain resistance for a pad

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Atre

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Hello,

Can anyone help me with how can I specify an external resistance for an
open-drain output-pad in Design Compiler.

Thanks in advance!
 

Atre said:
Hello,

Can anyone help me with how can I specify an external resistance for an
open-drain output-pad in Design Compiler.

Thanks in advance!
Click to expand...

Are you talking about the I2C pads. If yes then I can give you, related info.
 


If you can give me that kind of info......

Is it related to Design Compiler (Synopsys)?

10x!
 


Infact I can give the I2C specs doc, in which it is given how to select the external resistance value. Please go to page no. 40 of the attached doc & choose the value according to your specs(basically this value of the resistance is dependent on the supply voltage).
 

Well, that doesn't help... What I need is a way to specify in Design Compiler such thing. I mean, I know the resistance value (ie. 200 ohm) and I want to tell this to Synopsys. How can I do that??

10x!
 

may be you can add pad after DC ,add I/O pad at netlist after you had compiled by hand directly!
 

If you want to use internal pull-up resistor, you need to have this kind of pad. If you want to declare external pull-up resistor in your simulation testbench, you just need to use as like as below:

pullup p1(SCL);
pullup p2(SDA);
 

Hi, Atre

You can specify the tri-state pad for your open-drain pin. Then skip the synthesis with "dont_touch".

Good Luck
 

AlexWan said:
Hi, Atre

You can specify the tri-state pad for your open-drain pin. Then skip the synthesis with "dont_touch".

Good Luck
Click to expand...

Thank, I hope it would work this way.... I kinda dropped this for some time, but I hope I can fix it.

Thanks!
 



It is a good pdf ... thanks...
 

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