This chapter covers device and circuit aspects of low-power analog CMOS circuit design. The fundamental limits constraining the design of low-power circuits are first recalled with an emphasis on the implications of supply voltage reduction. Biasing MOS transistors at very low current provides new features but requires dedicated models valid in all regions of operation including weak, moderate and strong inversion. Low-current biasing also has a strong influence on noise and matching properties. All these issues are discussed, together with the particular aspects related to passive devices and parasitic effects. The design process has to be supported by efficient and accurate circuit simulation. To this end, the EKV compact MOST model for circuit simulation is shortly presented. The use of the basic concepts such as pinch-off voltage, inversion factor and specific current are highlighted thanks to some very simple but fundamental circuits and to an effective use of the model. New design techniques that are appropriate for low-power and/or low-voltage circuits are presented with an emphasis on the analog floating point technique, the instantaneous companding principle, and their application to filters.

A promising new approach to shorten the design trajectory of analog integrated circuits without giving up functionality is formed by the class of dynamic translinear circuits. This paper presents a structured design method for this young, yet rapidly developing, circuit paradigm. As a design example, a 40-¯A 2-V dynamic translinear PLL, used as an FM demodulator, is presented. I. Introduction Electronics design can be considered to be the mapping of a set of mathematical functions onto silicon. For discrete-time systems, of which the digital systems today are by far the most popular, this comes down to the implementation of a number of difference equations, whereas for continuous-time systems, often denoted by the term analog, differential equations are the starting points. In mixed analog-digital systems, the analog parts, however, often occupy less than ten percent of the complete, i.e., the mixed analog-digital circuitry, whereas their design trajectory is often substantially longe...

Abstract — A simple methodology for implementation of low-order, current-mode, log-domain filters in CMOS technology is presented. The key transistors in the circuit are operated in weak inversion and in contrast with previous approache s may pass into the triode regime. The concept is particularly suited to implementation in silicon-on-insulator technology, because dielectric isolation of the transistors eliminates leakage currents, and because influence of the body effect on circuit function is limited. Very long time constants, on the order of 1s or more, are obtainable. A simple elaboration of the basic unit circuit allows the time constant to be controlled by a bias current.

In this thesis a new signal processing technique is presented. This technique exploits the use of pulses as the signalling mechanism. This Palmo 1 signalling method applied to signal processing is novel, combining the advantages of both digital and analogue techniques. Pulsed signals are robust, inherently low-power, easily regenerated, and easily distributed across and between chips. The Palmo cells used to perform analogue operations on the pulsed signals are compact, fast, simple and programmable.