In this paper, the strong inversion MOS analog of the recently propose
d class of log-domain filters, or translinear filters, is proposed. Th
e dynamic root-domain principle, or dynamic voltage-translinear princi
ple, exploits the quadratic law, describing the MOS transistor in the
strong inversion region, both to perform an expanding V-I conversion o
f the capacitor voltages and to implement multiplications and square r
oots of currents based on the voltage-translinear principle. The prese
nted theory is applied to the design of a current-controlled two-integ
rator oscillator. Experiment results of a pure CMOS test IC show the f
easibility of the root-domain principle. The realized oscillator has a
THD of -42 dB and is linearly frequency tunable across 1.3 decades.