OpenAccess view save abort with multiplier m > 1 in XFAB XH018
Luca
Monday 27th April 2026
Dear Support,
I am having a save problem in OpenAccess layout view with the XFAB XH018 PDK when a MOS device has multiplier m > 1. Everything works correctly when m = 1.
By checking the netlist generated from the layout, I can see that when `m = 3`, three physical instances are created and all of them are assigned the same instance name. This seems to be the reason why the OpenAccess view save aborts.
At the moment, the only way I can save the layout is to flatten the two additional instances generated by the multiplier.
Could you please confirm whether this is the root cause, and how this case should be handled correctly in LayoutEditor?
Best regards
Jürgen LayoutEditorFull Monday 27th April 2026
Hi Luca,
Thanks for reporting this issue. Yes, this is a bug in the OpenAccess output when a multiplier >1 is in use. We will fix it with the next update. As a workaround you don't need to flatten them. You can call the properties window of the cellreference with the two addition instances, edit it attributes and renaming the device name. The two instances will then be handle as three different devices in the OpenAccess export. But as mentioned before we will fix the problem with the next update.
Luca
Tuesday 28th April 2026
Hi Jürgen,
Thanks for the quick reply. I tried renaming the additional instances as suggested. The OpenAccess save then works, but the schematic/layout association is lost and the connections are no longer preserved correctly.
I also tried names like M1<0>, M1<1> or using underscores, but the result is the same.
Is there a recommended naming/indexing method that keeps the multiplied layout devices associated with the original schematic instance?
Jürgen LayoutEditorFull Tuesday 28th April 2026
Hi Luca, Do you happen to have access to an OpenAccess layout view, created with another tool, that contains a reference to a device with a multiplier, and could you make it available to us? After reviewing the OpenAccess documentation, it's still not entirely clear to us what OpenAccess needs to store it. I could also submit a support request to the OpenAccess developers, but from experience, I know it takes months to get a response. A short example would be the quicker solution.
Luca
Thursday 30th April 2026
Hi Jürgen,
Unfortunately, we do not have access to another layout tool that can save an OpenAccess layout view with a MOS device using a multiplier greater than 1. At the moment we are using LayoutEditor only, so I am not able to provide a reference OpenAccess example generated by a different tool.
In the meantime, we can keep using the instance-renaming workaround you suggested where possible.
I would also like to ask you another question related to the XFAB XH018 PDK integration in LayoutEditor. The PDK includes abutment functionality in the Synopsys PyCells. Is this functionality already supported or integrated in LayoutEditor, or does it require additional user-side code or configuration to work?
Thank you for your support.
Jürgen LayoutEditorFull Thursday 30th April 2026
Hi Luca, Never mind. The storage of devices with multiplier will work with the next update. Just the validation that our solution is the intended way for OpenAccess usage will need some time. And yes, Synopsys PyCell supports abutment functionality. It is triggered by a parameter of the device parameters. A manual triggering by changing this parameter is also supported by the LayoutEditor. However, a triggering by snapping the device at a matching position is not supported. So you always need to activate it manually.