This survey presents an overview of recent advances in the state of the art for computer-aided design (CAD) tools for analog and mixed-signal integrated circuits (ICs). Analog blocks typically constitute only a small fraction of the components on mixed-signal ICs and emerging systems-on-a-chip (SoC) designs. But due to the increasing levels of integration available in silicon technology and the growing requirement for digital systems to communicate with the continuous-valued external world, there is a growing need for CAD tools that increase the design productivity and improve the quality of analog integrated circuits. This paper describes the motivation and evolution of these tools and outlines progress on the various design problems involved: simulation and modeling, symbolic analysis, synthesis and optimization, layout generation, yield analysis and design centering, and test. This paper summarizes the problems for which viable solutions are emerging and those which are still unsolved.

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Computer-aided design of analog and mixed-signal integrated circuits

We describe a new method for determining component values and transistor dimensions for CMOS operational amplifiers (op-amps). We observe that a wide variety of design objectives and constraints have a special form, i.e., they are posynomial functions of the design variables. As a result, the amplifier design problem can be expressed as a special form of optimization problem called geometric programming, for which very efficient global optimization methods have been developed. As a consequence we can efficiently determine globally optimal amplifier designs or globally optimal tradeoffs among competing performance measures such as power, open-loop gain, and bandwidth. Our method, therefore, yields completely automated sizing of (globally) optimal CMOS amplifiers, directly from specifications. In this paper, we apply this method to a specific widely used operational amplifier architecture, showing in detail how to formulate the design problem as a geometric program. We compute globally optimal tradeoff curves relating performance measures such as power dissipation, unity-gain bandwidth, and open-loop gain. We show how the method can he used to size robust designs, i.e., designs guaranteed to meet the specifications for a variety of process conditions and parameters.

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Optimal design of a CMOS op-amp via geometric programming

Methods of Feasible Directions. By G. Zoutendijk. Pp. 126. 30s. 1960. (D. van Nostrand Co. London)

A hierarchically structured framework for analog circuit synthesis is described. This hierarchical structure has two important features: it decomposes the design task into a sequence of smaller tasks with uniform structure, and it simplifies the reuse of design knowledge. Mechanisms are described that select from among alternate design styles and translate performance specifications from one level in the hierarchy to the next lower, more concrete level. A prototype implementation, OASYS, synthesizes sized transistor schematics for CMOS operational amplifiers from performance specifications and process parameters. Measurements from detailed circuit simulation and from actual fabricated analog ICs based on OASYS-synthesized designs demonstrate that OASYS is capable of synthesizing functional circuits. >

OASYS: a framework for analog circuit synthesis

A silicon compilation system for CMOS operational amplifiers (OPASYN) is discussed. The synthesis system takes as inputs system-level specifications, fabrication-dependent technology parameters, and geometric layout rules. It produces a design-rule-correct compact layout of an optimized operational amplifier. The synthesis proceeds in three stages: (1) heuristic selection of a suitable circuit topology; (2) parametric circuit optimization based on analytic models; and (3) mask geometry construction using a macro cell layout style. The synthesis process is fast enough for the program to be used interactively at the system design level by system designers who are inexperienced in operational amplifier design. >

OPASYN: a compiler for CMOS operational amplifiers

DELIGHT.SPICE is the union of the DELIGHT interactive optimization-based computer-aided-design system and the SPICE circuit analysis program. With the DELIGHT.SPICE tool, circuit designers can take advantage of recent powerful optimization algorithms and a methodology that emphasizes designer intuition and man-machine interaction. Designer and computer are complementary in adjusting parameters of electronic circuits automatically to improve their performance criteria and to study complex tradeoffs between multiple competing objectives, while simultaneously satisfying multiple-constraint specifications. The optimization runs much more efficiently than previously because the SPICE program used has been enhanced to perform DC, AC, and transient sensitivity computation. Industrial analog and digital circuits have been redesigned using this tool, yielding substantial improvement in circuit performance. >

DELIGHT.SPICE: an optimization-based system for the design of integrated circuits

Motivated by a control system example, a new methodology is proposed for tackling optimal design of engineering systems. This methodology emphasizes designer's intuition and man-machine interaction. It includes a classification of specifications into various types and a scaling of specification space and parameter spaces based on the designer's knowledge of the particular application. An algorithm is proposed for solving the resulting constrained ‘minimax’ optimization problem and its convergence is proved. Finally, an application-oriented user front-end is presented. The methodology discussed in this paper has been implemented in the DELIGHT system and has been successfully used in various types of applications.

An application-oriented, optimization-based methodology for interactive design of engineering systems†

After the advantages of methods of feasible directions in an engineering design environment are pointed out, several modifications to the classical scheme are proposed, aimed at improving computational efficiency while preserving convergence properties. First, an abstract algorithm model is set up and a set of sufficient conditions to ensure convergence is given. Several modifications are proposed, inspired by difficulties arising in an engineering design environment, and it is shown that the resulting algorithms satisfy the sufficient conditions just mentioned. An integrated-circuit bipolar operational amplifier is optimized in order to show the improvement in computation efficiency that the proposed enhancements can provide.

Enhanced methods of feasible directions for engineering design problems

DELIGHT. SPICE: an optimization based system for the design of integrated circuits

http://link.springer.com/content/pdf/10.1007/978-94-009-8603-9_23.pdf

W. Nye

Papers

DELIGHT.SPICE: an optimization-based system for the design of integrated circuits

An application-oriented, optimization-based methodology for interactive design of engineering systems†

Enhanced methods of feasible directions for engineering design problems

DELIGHT. SPICE: an optimization based system for the design of integrated circuits

A Software System for Optimization Based Interactive Computer-Aided Design