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RF Electronics Appendix 1: Importing Local Vendor and Spice Files Page 387 2022, C. J. Kikkert, James Cook University, ISBN 978-0-6486803-9-0. figure A1.4.The Spice files are text files, so one can use a standard text editor to inspect and edit the spice files if needed. Figure A1.4. AWR DE help on importing PSpice files. As an example of the process, the Spice model of an AD797 [5] operational amplifier is required. From the Analog Devices web site search for AD797, then select and download the spice model. That is a .cir file. In a Cadence AWR Design Environment project, select Netlist Import Netlist and select the ad797.cir file to import. In a circuit Schematic, the spice file can then be added by "Draw Add Subcircuit" and then selecting the AD797 element. It is desirable to change the square box SUBCKT symbol to one commonly used for OpAmps, by selecting "Properties Symbol" and then selecting OpAmp6@APLAC.syf as the symbol to be used. That then allows a schematic like figure 10.17 to be produced. The simulation will show some warnings where resistors R = 0 are replaced with small non-zero values. If it is desirable not to have errors, the netlist can be edited in a text editor to replace the zero ohm resistors with the suggested values, like R2 = 1e-6. That will then allow an easier identification of any other errors generated by the simulation. The same process is used for importing Spice files for other devices such as transistors, or diodes. The models for Texas Instruments devices are no longer directly available from their web site. The PSpice for TI [X] software by Cadence can be used for PSpice simulation of many of their devices. PSpice for TI can be downloaded and operated without cost. That software can be used to produce the required PSpice files for import into AWR DE. As an example, the PSpice file for the THS4021/4022 OpAmp used in figure 10.20 is generated. To create the PSpice file, run PSpice for TI. Create a design and place the desired component on the schematic page. In PSpice Part Search, select Texas Instruments Amplifiers Operational Amplifiers High Speed op amps. Then place the THS4021 part on the schematic. Left click on the OpAmp to select it, then right click RF Electronics: Design and Simulation 387 www.cadence.com/go/awr