open-source-silicon.dev

<https://github.com/IHP-GmbH/IHP-Open-PDK/issues/428|#428 Documentation of Rppd>
Issue created by <https://github.com/EngGhaith|EngGhaith>
Hi everyone,  
I need some help due to lack of device documentation:  
In Xschem:

<https://private-user-images.githubusercontent.com/178785944/429881061-948819a8-d823-414f-94ce-69e7e8137ad7.png?jwt=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJnaXRodWIuY29tIiwiYXVkIjoicmF3LmdpdGh1YnVzZXJjb250ZW50LmNvbSIsImtleSI6ImtleTUiLCJleHAiOjE3NDM3MDEzMDksIm5iZiI6MTc0MzcwMTAwOSwicGF0aCI6Ii8xNzg3ODU5NDQvNDI5ODgxMDYxLTk0ODgxOWE4LWQ4MjMtNDE0Zi05NGNlLTY5ZTdlODEzN2FkNy5wbmc_WC1BbXotQWxnb3JpdGhtPUFXUzQtSE1BQy1TSEEyNTYmWC1BbXotQ3JlZGVudGlhbD1BS0lBVkNPRFlMU0E1M1BRSzRaQSUyRjIwMjUwNDAzJTJGdXMtZWFzdC0xJTJGczMlMkZhd3M0X3JlcXVlc3QmWC1BbXotRGF0ZT0yMDI1MDQwM1QxNzIzMjlaJlgtQW16LUV4cGlyZXM9MzAwJlgtQW16LVNpZ25hdHVyZT00NzE0ODdkNmE0MDM0MWYwMzUzYjA0OTc4YjA3MTBlMGI4OGZmNGI0YmYzZjZlNjIzY2M0ZTQ3N2VlZGM4ZWM1JlgtQW16LVNpZ25lZEhlYWRlcnM9aG9zdCJ9.PNP-0xi_AvERt-b7TjDiHmXpEYpG3ksyg7OmHEl_8rM|[Image](https://private-user-images.githubusercontent.com/178785944/429881061-948819a8-d823-414f-94ce-69e7e8137ad7.png?jwt=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJnaXRodWIuY29tIiwiYXVkIjoicmF3LmdpdGh1YnVzZXJjb250ZW50LmNvbSIsImtleSI6ImtleTUiLCJleHAiOjE3NDM3MDEzMDksIm5iZiI6MTc0MzcwMTAwOSwicGF0aCI6Ii8xNzg3ODU5NDQvNDI5ODgxMDYxLTk0ODgxOWE4LWQ4MjMtNDE0Zi05NGNlLTY5ZTdlODEzN2FkNy5wbmc_WC1BbXotQWxnb3JpdGhtPUFXUzQtSE1BQy1TSEEyNTYmWC1BbXotQ3JlZGVudGlhbD1BS0lBVkNPRFlMU0E1M1BRSzRaQSUyRjIwMjUwNDAzJTJGdXMtZWFzdC0xJTJGczMlMkZhd3M0X3JlcXVlc3QmWC1BbXotRGF0ZT0yMDI1MDQwM1QxNzIzMjlaJlgtQW16LUV4cGlyZXM9MzAwJlgtQW16LVNpZ25hdHVyZT00NzE0ODdkNmE0MDM0MWYwMzUzYjA0OTc4YjA3MTBlMGI4OGZmNGI0YmYzZjZlNjIzY2M0ZTQ3N2VlZGM4ZWM1JlgtQW16LVNpZ25lZEhlYWRlcnM9aG9zdCJ9.PNP-0xi_AvERt-b7TjDiHmXpEYpG3ksyg7OmHEl_8rM)>

What is the parameter b, and which impact on accuracy/current density/...etc. should it give?  
In the docs of process spec it says that for prceision resistors use w&gt;=2µm, but which b is then preffered?

In KLayout:

<https://private-user-images.githubusercontent.com/178785944/429877830-fcb5d425-ed2a-4726-a0c4-345e21051c20.png?jwt=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJnaXRodWIuY29tIiwiYXVkIjoicmF3LmdpdGh1YnVzZXJjb250ZW50LmNvbSIsImtleSI6ImtleTUiLCJleHAiOjE3NDM3MDEzMDksIm5iZiI6MTc0MzcwMTAwOSwicGF0aCI6Ii8xNzg3ODU5NDQvNDI5ODc3ODMwLWZjYjVkNDI1LWVkMmEtNDcyNi1hMGM0LTM0NWUyMTA1MWMyMC5wbmc_WC1BbXotQWxnb3JpdGhtPUFXUzQtSE1BQy1TSEEyNTYmWC1BbXotQ3JlZGVudGlhbD1BS0lBVkNPRFlMU0E1M1BRSzRaQSUyRjIwMjUwNDAzJTJGdXMtZWFzdC0xJTJGczMlMkZhd3M0X3JlcXVlc3QmWC1BbXotRGF0ZT0yMDI1MDQwM1QxNzIzMjlaJlgtQW16LUV4cGlyZXM9MzAwJlgtQW16LVNpZ25hdHVyZT0zYjg2ZGRlNDZkMmViM2E3NWI2Mzc4NjNkNmMxZmZlYzI1MzhjODg0ZjFiNDJkMjViOTQ5NDZjYjNiNzVlZjZkJlgtQW16LVNpZ25lZEhlYWRlcnM9aG9zdCJ9.l7gF9OsnA3XIx2kRXpa8rBTdhDOL-6kMxB7VvJDJqn4|[Image](https://private-user-images.githubusercontent.com/178785944/429877830-fcb5d425-ed2a-4726-a0c4-345e21051c20.png?jwt=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJnaXRodWIuY29tIiwiYXVkIjoicmF3LmdpdGh1YnVzZXJjb250ZW50LmNvbSIsImtleSI6ImtleTUiLCJleHAiOjE3NDM3MDEzMDksIm5iZiI6MTc0MzcwMTAwOSwicGF0aCI6Ii8xNzg3ODU5NDQvNDI5ODc3ODMwLWZjYjVkNDI1LWVkMmEtNDcyNi1hMGM0LTM0NWUyMTA1MWMyMC5wbmc_WC1BbXotQWxnb3JpdGhtPUFXUzQtSE1BQy1TSEEyNTYmWC1BbXotQ3JlZGVudGlhbD1BS0lBVkNPRFlMU0E1M1BRSzRaQSUyRjIwMjUwNDAzJTJGdXMtZWFzdC0xJTJGczMlMkZhd3M0X3JlcXVlc3QmWC1BbXotRGF0ZT0yMDI1MDQwM1QxNzIzMjlaJlgtQW16LUV4cGlyZXM9MzAwJlgtQW16LVNpZ25hdHVyZT0zYjg2ZGRlNDZkMmViM2E3NWI2Mzc4NjNkNmMxZmZlYzI1MzhjODg0ZjFiNDJkMjViOTQ5NDZjYjNiNzVlZjZkJlgtQW16LVNpZ25lZEhlYWRlcnM9aG9zdCJ9.l7gF9OsnA3XIx2kRXpa8rBTdhDOL-6kMxB7VvJDJqn4)>

Which parameters to manipulate and which to be "automatically" calculated?  
Because the GUI allows me to manipulate everything and do not update other parameters automatically. E.g. If I changed Imax to 3m, It would not change neither w, nor l nor R.  
It would be nice to provide any infos about the other parameters also.

Thank you in advance.  
Ghaith.
<https://github.com/IHP-GmbH/IHP-Open-PDK|IHP-GmbH/IHP-Open-PDK>