An Open Loop Phase Shifter and Frequency Synthesizer

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 point of two ramps will be detected as the middle point of high or low duration which will be full-range recovered for 90° shifting operation. Four phases in 10 MHz frequency can be generated by 3mW power consumption and 60μ×60μ area. All circuits have been simulated in 0.35μ CMOS technology.