Systematic circuit design and analysis using generalised g _m / I _D functions of MOS devices

Abstract

The conventional approach to implementing analogue integrated circuits in nano-scale complementary metal oxide semiconductor (CMOS) technologies relies basically on circuit simulations using the SPICE models provided by the foundries. Depending on the circuit complexity, the designer should, however, spend a significant amount of time sizing the metal oxide semiconductor field effect transistors such that maximum efficiency is achieved for minimum power consumption and silicon area. Analytical-based design procedures can assist the designer in confronting the sizing challenge of the metal oxide semiconductor (MOS) devices. The procedures are, however, dependent on circuit topology, model parameters, and device physics. This study aims at presenting a systematic approach for analysis and design of analogue circuits in scaled CMOS. For this purpose, the behaviour of short-channel MOS devices is characterised in various process and temperature corners using an updated matrix representation of different device scales, bias conditions, and small-signal parameters. The details to effectively extract the matrix derivation of the technology model files are presented, enabling to devise generalised functions for the design and analysis of the circuits. The design examples include a 0.39 V-28 µA reference circuit, and a 7.50 µA/V operationaltransconductance amplifier with 1.0 V voltage supply in 90-nm CMOS.

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