Design-oriented analysis of log-domain circuits

A simple change in the form of the state variables clarifies previously published analyses of log-domain circuits. The change highlights the role of bias currents and leads to a simple design procedure based an self-contained building blocks. A new nonlinear equivalent circuit is presented fur the building blocks with a topology that emphasizes the applicability of small-signal analysis for log-domain circuits. The nonlinear equivalent circuit suggests a novel single-ended inverting cell that works at very low supply voltage V_DD and dues not require p-n-p transistors