2008 Volume E91.A Issue 2 Pages 491-496
This paper presents a new open-loop phase shifter and frequency synthesizer which can be implemented by small hardware. In the proposed method the differential square wave is converted to a differential ramp. Then the cross points of two ramps are detected as the middle points of high or low durations and are recovered to full digital levels, for 90° shifting operation. 4-phases in 50MHz frequency can be generated by 3.5mW power consumption and 60μm×60μm area. All circuits have been simulated in 0.35μm CMOS technology.