A 2.4-GHz spur-cancelled fractional-n frequency synthesizer with PFD/DAC structure for WSN application

A 2.4-GHz wideband fractional-N frequency synthesizer utilizing PFD/DAC structure for Wireless Sensor Network (WSN) Application is presented. In this synthesizer, hybrid of phase/frequency detector and compensated digital-to-analog converter (PFD/DAC) is utilized to achieve phase noise performance as an integer-N synthesizer. The synthesizer is implemented with wide 400 kHz loop bandwidth and 4 us setting time. The chip occupies 1.9 mm2 and consumes 16.4 mA at 1.8-V supply.