1. Technology VLSI Silicon Sensor and System Lab Digitally-Controlled Cell-based Oscillator With Multi-Phase Differential Outputs 603410065 楊佳榮 603410014 蔡宜哲 Dept. of CSIE, National Chung Cheng University, EA408, No. 168, University Rd.,Min-Hsiung, Chia-Yi, Taiwan, Email: jzyang@s3lab.org URL: http://www.s3lab.org@s3lab.orghttp://www.s3lab.org

2. 2 Silicon Sensor and System Lab Introduction The digitally-controlled oscillator (DCO) performs digital code to frequency conversion. DCO could have larger frequency tuning range to accommodate process corner variations, however, it has poorer phase noise performance than oscillators. Fully digitally-controlled oscillator design in deep-submicron CMOS process with fine frequency resolution and low phase noise performance becomes an emerging issue.

3. 3 Silicon Sensor and System Lab Digitally Controlled Oscillator (DCO) Conventional DCO is composed of odd number of inverter which can change the oscillation path`s driving ability so as to change its delay time as well as frequency. In an analog delay cell, the delay time is controlled by its operating current or voltage.

4. 4 Silicon Sensor and System Lab Experimental results DCO layout

5. 5 Silicon Sensor and System Lab Experimental results DCO design summary

6. 6 Silicon Sensor and System Lab Conclusion The cell-based DCO architecture has an advantage of ease of process migration. The DCO has differential outputs and each stage`s output can have good duty cycle performance. The hierarchical control parts can enhance the DCO`s frequency resolution.