Fully integrated frequency synthesizer design for wireless network application with digital programmability

A 2.60-GHz integer-N frequency synthesizer was designed and implemented in SiGe BiCMOS technology. The single chip includes fully integrated VCO (voltage control oscillator) as well as LPF (loop-filter). The synthesizer provides a wide frequency range of 300 MHz, which covers 2.59-2.66 and 2.8725-2.9025 GHz with a single VCO. Digital technique is employed at VCO and charge-pump to cover the frequency range and cater for process variation. Using reference frequency of 2.5 MHz the fabricated prototype demonstrates a settling time of 32 μs, and reference spur below -56 dBc. The synthesizer's phase noise is -115 dBc/Hz at 1.0-MHz offset frequency. It consumes approximately 42 mW power from a 3.0 V single supply, with a total active area of 2.34 mm².