Automated VCO Synthesis

Final Conclusion

Starting from the vague and simple definition of what is considered in this work to be a functional block, a structured design methodology is proposed. It is called the DLE (Design-Level Entry) methodology since the point-ofentry of the methodology is situated at the level of the functional blocks an analog designer is working with, having a system level above it and a physical implementation level below. The main idea behind it is that a designer should be able to benefit from the use of the methodology without having to change his everyday design practice.

For the DLE tool an implementation of its Block Sizing Function is proposed that is based on the use of a Design Template consisting of a fixed topology and a set of Design Directives, being the knowledge of the designer about this specific topology of the functional block under consideration. Within the Design Template, layout information can also be included. Furthermore, the designer can indicate within the Design Template a limited set of independent parameters for which he wants an optimizer to determine the set of values that will minimize a cost function evaluating the circuit performance.

As an example of such a Design Template-based design, the CYCLONE tool for the automated design of optimized LC-tank VCO’s is presented. The Design Template here consists of the VCO topology and the formula’s needed to calculate the gain cell and varactor diode sizes given a certain set of inductor parameters. Layout parasitics are taken into account within the Design Template. The use of the tool has been demonstrated with some examples.