A varactorless technique for tuning LC oscillators based on loop gain adjustment

A novel technique for tuning LC oscillators is introduced in this paper. The proposed technique provides a much wider tuning range than conventional methods. It has the advantage of not relying on the value of any resistive/reactive element to achieve tunability, hence tuning ranges are no longer limited by component values realizable by technology. The technique can be extended to other applications requiring programmability of some system poles. A current-tuned LC oscillator is implemented in 0.13-mum technology to verify the technique introduced herein. The oscillator operates at 2.8 GHz, has a tuning range of 71% extendable to 98%, and a maximum power dissipation of 6 mW.