One microsecond fast acquisition 2.4 GHz low voltage frequency synthesizer for frequency-hopping spread spectrum mobile communications

A fast acquisition frequency synthesizer designed for 2.4 GHz band frequency hopping CDMA handheld phones is discussed. The proposed frequency synthesizer can switch to a new channel within one microsecond while operating at 3 V. In order to achieve fast acquisition, low phase noise and low harmonic content under very low supply voltage, special designed voltage controlled oscillator, frequency doubler and switchable loop filter were adopted for optimum performance. The proposed design is suitable for the low voltage and low power handheld equipment. With minor modification, the design can be applied to other digital cellular applications.