Temperature and supply voltage compensated biasing for digitally controlled oscillators

This paper presents a current bias circuit for digitally controlled oscillators (DCOs). It consists of three individual current components with different supply voltage and temperature sensitivities and thereby allows to effectively compensate period variations with respect to supply voltage and temperature. This reduces the required fine tuning range for ADPLL application of the DCO. The concept is proven by a DCO circuit implementation in 65nm CMOS technology and verified by simulations and testchip measurements.