Design Of Wideband VCO For Multi-mode Multi-standard Receiver

The wireless communication technology, widely used in industry, medicine, manufacturing and other fields, is playing an increasingly important role in today’s society. Wireless communication technology applications in satellite communications, vehicle networks, wireless LANs and other aspects of personal communication is a broad market. With the rapid development of mobile communication technology, many wireless communication standards have been proposed, such as GSM, WCDMA, LTE, WLAN, GPS, and so on. In order to adapt to the current trend of wireless communication development, a receiver which supports multiple communication standards has become the focus of the world. Frequency synthesizer is widely used in wireless communication systems, providing the local oscillator signal to frequency conversion and channel selection. Voltage controlled oscillator(VCO)is part of a frequency synthesizer, determining the frequency range of the frequency synthesizer and phase noise performance. VCO must meet the low phase noise, low power requirements and covers the entire frequency range.A wideband VCO designed in TSMC 0.18-μm CMOS technology is presented in this thesis which is applied to multi-standard, multi-band wireless receiver. The oscillator has a dual-mode VCO and a tuning-range extension circuit, which consists of a divider chain and a multiplexer. The dual-mode VCO uses 5 th-resonator based on coupled inductors, and 5-bit switched capacitor array extending the tuning range. Varactors bank is employed to improve the phase noise from Amplitude Modulation to Phase Modulation up conversion, while the current-reused topology lowers the dc power consumption. Post-simulation results show that VCO covers 3.8-7.6 GHz frequency range and the phase noise at 1MHz offset is from-111.3dBc/Hz to-109dBc/Hz over the entire frequency tuning range. The supply voltage is 1.8V, core VCO consuming 6-12mA of current. The whole circuit to work properly and the operating current is less than 40mA. The whole territory is 1075μm× 685μm, with a total area of approximately 0.736mm2.