The CIR file extension is associated with PSpice, a full-featured, native analog and mixed-signal circuit simulator, developed by Cadence Design Systems, Inc.. The .cir files describe the analysis performed with its parameters.
The CIR file extension is associated with the Supermax ECAD. Supermax ECAD application was developed by the Mentor Graphics and it was used for designe PCB boards. Now is discontinued product. The Supermax ECAD files can open for example EDAbase.