MOS only oscillator using adder and subtractor circuits

In this paper an NMOS based sinusoidal oscillator is presented. The circuit is constructed with voltage-mode (VM) NMOS-based analog adder and subtractor circuits which respectively perform V₁+V₂ and V₁-V₂ operations on the input voltages. The most important feature of the proposed circuits is their extremely simple structures containing only twelve NMOS transistors (six for the adder, six for the subtractor). Another significant advantage of the proposed circuits is that no external passive components are being used. The post-layout simulations of the proposed oscillator circuit have been executed using TSMC 0.25 μm process parameters with ±1.25 V power supply voltage.