A Crystal-Less Clock Generator for Low-Power and Low-Cost Sensor Transceivers with 12.9MHz-to-3.3GHz Range, 16.67ppm/°C Inaccuracy from -25°C to 85°C, and 0.25us Settle-Time.

In the field of sensor system design, the need for low-power and cost-effective solutions is growing. Existing clock generation technologies for sensor transceivers, however, rely on external references or high-cost components, introducing economic constraints. To address these issues, there is on-going research on utilizing on-chip RC oscillators (RCOs) to generate clocks without external references [1], [2]. The objective is to deliver precise frequency outputs that are immune to variations in process, voltage, and temperature. Particularly, resistors with Proportional to Absolute Temperature (PTAT) and Complementary to Absolute Temperature (CTAT) characteristics are often used to balance temperature changes [3]. However, due to high fabrication and measurement costs, these techniques may not suitable for low-cost sensor systems. Therefore, there is a compelling need for the design of accurate RCOs that employs a single type of resistor.