Abstract
In this paper, we propose a very simple ring voltage-controlled oscillator (VCO) structure for use in a variety of applications ranging from the data encryption and mathematical simulation to the built-in-self test (BIST) of RF receivers. The proposed ring VCO has two advantages; its linearity is greatly improved compared to published VCO and the circuit is temperature compensated through a bandgap reference. The chip is fabricated in AMS 0.35 mu m CMOS technology with 2.5 V power supply. The total area is 0.02 mm(2). A series of measurement results confirm the validity of the proposed circuit. Operating at 2.5 V, the output frequency is within 300 +/- 2 MHz over the temperature range of -20 degrees C to 80 degrees C with power consumption of 400 mu W.