Power consumption of analog circuits: a tutorial

Abstract

A systematic approach to the power consumption of analog circuits is presented. The power consumption is related to basic circuit requirements, as dynamic range, bandwidth, noise figure and sampling speed and is considering basic device and device scaling behavior. Several kinds of circuits are treated, as samplers, amplifiers, filters and oscillators. The objective is to derive lower bounds to power consumption in analog circuits, to be used as design targets when designing power-constrained analog systems.

Towards Power Centric Analog Design

“…More recently, Sundström et al, presented a quantitative analysis of the lower bounds of the power consumption of analog-to-digital converters [15]. That work was then generalized by Svensson and Wikner [16], to a large extent based on Bults analysis, to a first attempt to realize the goal of an analog correspondence to eq. (1).…”

“…(1). Abidi discussed power-conscious design of wireless circuits in [17], and Nilsson [18] later attempted to extend the analog power concept in [16] to such circuits. Homayoun and Razavi [19] recently presented some innovative ideas for power saving in a wireless receiver.…”

“…A good starting point in the discussion of analog power consumption is the ideal sampler (the sampleand-hold circuit) [8,16]. An ideal sampler will follow an analog signal and then sample and hold its value for a period of time.…”

“…We also included the digital case in the figure, in order to demonstrate the different behavior of the two. The actual data is taken from [16] and corresponds to a simple filter designed in analog or digital technique. In most practical cases the dynamic range requirements are large enough to make eq.…”

“…where  is a noise factor and Bn is the system noise bandwidth [16]. In the following we neglect noise contributions from other sources than the transistor drain current (as the drain current noise normally dominates).…”