Design tradeoffs for voltage controlled crystal oscillators with built-in calibration mechanisms

Timing is a critical issue in communication systems, especially for synchronous communications. These show a high dependence on the clock signal purity due to errors that can be introduced into the decision process. This paper addresses the design, on a 130nm CMOS process, of a Radiation Tolerant Voltage Controlled Quartz Crystal Oscillator (VCXO), including techniques to reduce the influence of radiation and noise on its performance. The VCXO is included on a PLL designed to work within High Energy Physics (HEP) experiments.