Comment by henrikf | Hacker News Reader

Comment by henrikf | Hacker News Reader

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This is a very fast BiCMOS process with both MOSFETs and bipolar transistors. Some digital logic can be implemented with MOSFETs but since they are 130 nm it's not very competitive with smaller cutting edge CMOS processes. Bipolar transistors are really the whole point of choosing this process and it's aimed for implementing analog and RF circuits. Bipolar transistors are extremely fast and can be used to make amplifiers operating at >200 GHz. MOSFETs can be used to implement some simple digital blocks for controlling the RF blocks.

I have made several tapeouts with this process and I have very good experiences with it. Compared to other open source PDKs that Google has open sourced previously this one is quite modern and offers very good RF performance.

It doesn't seem quite ready for design yet. Transistor models and stackup are published so schematic level simulation is possible. There is a roadmap chart in the repository (https://github.com/IHP-GmbH/IHP-Open-PDK/blob/main/ihp-sg13g...) and it seems that they are going to offer free MPW runs.

Isn't this what's used for military applications like AESA radars? If so how come it's open source?

What's open sourced here is the design kit. Designed chips need to be sent to IHP to be manufactured.

SiGe isn't also that useful for military radar applications. Compared to SiGe GaN has much greater breakdown voltage which leads to greater output power and better efficiency. It's possible to get 10 to 100 times more output power from GaN chip compared to SiGe. It isn't really possible to make high performance long range radar with just SiGe although it could be used in some parts of it.

Is there any FOSS you can use these PDKs with?

For this PDK there is only limited support (it is only in preview!) for klayout and ngspice - which are a FOSS layout tool and circuit simulator respectively. If you want to play with whats available, someone put up a colab script here:

https://colab.research.google.com/gist/proppy/f63686b02309e2...

The other two open PDKs, SKY130 and GF180MCU, have a more complete ecosystem the major tools being the opencircuitdesign suite, xschem and the OpenRoad project. If you're still interested, there's an easy to use docker container that has most of the tools in question already installed:

https://github.com/iic-jku/iic-osic-tools

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