LAUSR

In this brief, an analytical model for the reliability-oriented design of injection-locked frequency divider (ILFD) is proposed. It is able to provide a clear evaluation of startup condition in the ring oscillator (RO)-based ILFD, which has not been clearly defined with the conventional zero-pole theory. A new startup condition analysis is presented and applied in designing an ILFD to achieve a reasonable compromise between a robust startup condition and a wide locking range. To verify this theory, a prototype is fabricated using a standard 0.18- ${\mu \text {m}}$ CMOS process, maintaining a reliable startup over potential variations of manufacturing or working conditions. The experimental results at industrial temperature ranges under different supply voltages suggest that the proposed divider is able to work robustly from 0.19 to 1.24 GHz with a maximum power consumption of 0.246 mW from a 1.2-V supply, while occupying a silicon area less than $20\times 30\,\,{\mu \text {m}^{2}}$ .