This paper presents a current-mode four-phase third-order quadrature oscillator (QO) using current differencing transconductance amplifiers (CDTA). The proposed thirdorder QO consists of three CDTAs and three grounded capacitors, and it could generate four quadrature current outputs. The oscillation condition and oscillation frequency could be electronically and independently adjusted. Moreover, the proposed third-order QO has low active and passive sensitivities. Cadence IC Design Tools post-layout simulation and experimental results are included to confirm all the theory.

Keywords: Current differencing transconductance amplifier (CDTA), Current mode, Quadrature oscillator