Mismatch Characterization of Ring Oscillators

We investigate the frequency matching of ring oscillators to study the matching of the non-static operation of identical high speed analog, digital and RF circuits. The oscillator test structures on a 0.25
μ
m CMOS technology operate in the 500MHz to 3GHz range. The non-static matching experimental results are compared to predictions based on DC matching parameters. Stage averaging versus device size averaging for constant frequency designs is investigated. Global variations and the long distance matching are also examined and compared.