Design And Research Of Frequency Synthesizer For ZigBee Transceiver

As a new kind of wireless communication technology, ZigBee is widely used inshort distance communication with the low power, low cost and large network size etc.advantages. RF transceiver Based on ZigBee is becoming research hotshot. The papermainly concerns in the design and research of frequency synthesizer in2.4GHz ZigBeeRF transceiver.Frequency synthesis technique and linearized model of PLL frequency synthesizerare firstly described, then some ways decreasing phase noise are gave. Combining withZigBee protocol, we determine performance index of designed frequency synthesizer.This paper pays more attention to the design of wideband LC voltage controlledoscillator. Discussion of integrated spiral inductor and variable capacitor is presentedin detail. For wideband VCO, design capacitor array dividing wide tuning range intomultiple narrow sub-band to decrease phase noise. To restrain power interference, takeinternal LDO as power supply. To stabilize the output amplitude, resistor array isdesigned for bias and give the auto amplitude control method. At the same timeinteger-N divider is proposed and mainly focus on high-speed, dual-modulus prescaler.The circuit is implemented in TSMC0.18μm CMOS process, simulation results are asfollows: power supply:1.8V; key circuit dissipation:1.68mW; output frequency range:4.46GHz~5.5GHz; kvco=60MHz/V; output amplitude810mV; phase noise:-114.2dBc/Hz@1MHz; dividers realize32/32.5frequency dividing. The simulationresults of designed circuits meet the transceiver system requirements.