2 Replies Latest reply on Feb 3, 2010 2:08 AM by lennart.granlund

    Pre-defined RF structures in DxD flow

    lennart.granlund

      Hi!

      I am kind of new to Expedition and DxDesigner, and maybe I am way out, but my dilemma is as follows:

       

      From my customer I have received some pre-defined RF structures; a Wilkinson divider/combiner and a delay line structure. These were delivered as GDSII files, which I converted to DXF format.

      I have chosen to treat them as components, i e drawn a schematic symbol with correct number of pins, and created a footprint cell, in which I have imported the DXF file. Each pin has received a simple padstack for routing, and the DXF structure defined as "Metallization area". From these, of course, I have created a Part.

       

      The problem is that inside these structures, 0402 SMD resistors are to be placed. In the Wilkinson case just one, and in the Delay line there are 22 of them. To make it even funnier, some of them share one pad between them.

      At present, in my layout I have the RF structures as separate cells, and ratnest connections to the 0402 resistors. When I try to place the resistor in its correct place, the DRC protests ("Cannot resolve immovable metal conflict"). I have defined special clearance rules for these areas, with 0 clearance everywhere, but it does not help.

       

      Basically, because of the way I have handled this, I need to allow cells to be placed on top of other cells. Is this at all possible, or should I go back to the schematic and re-think?

       

      I know that if I had had schematic ADS or AWR files, I could have imported them into thpse special RF libraries, and from that somehow automatically obtained parametrized RF structures in the layout. Unfortunately, all I have is the GDSII/DXF files.

       

      If anyone has a solution, please let me know.