Process and temperature insensitive CMOS oscillator using current sinker compensation

This article presents a simple complementary metal-oxide-semiconductor (CMOS) ring oscillator using a voltage-controlled delay and RS-latch, including a compensation circuit for the process and temperature variations.The compensation circuit, added to the original bias circuit, is a simple current sinker which is referenced through a current mirror circuit. The proposed oscillator was designed and implemented using a 0.13 μm CMOS process. The oscillator exhibited a significantly improved frequency variation of ±4.25% for a wide temperature range of from -40 to 80°C. Without the compensation circuit, the variation would have been ±13.39% from the center frequency of 2.33 MHz. The oscillator also showed a low sensitivity of 0.084% to process variation, according to a Monte-Carlo simulation with 1000 iterations.