2GHZ PLL Frequency Synthesizer for Zigbee Applications
ZigBee is an emerging short distance wireless communication technology. It is mainly used for short range, low power consumption and low transfer rate data applications A low power 2GHz PLL frequency synthesizer for Zigbee/IEEE 802.15.4 applications is presented. The current starve VCO is used to decrease power consumption and to improve noise characteristic of the synthesizer. The synthesizer employs a 1 MHz fully programmable divider with an improved TSPC 2/3 prescaler, a novel bit-cell for the programmable counters and PFD, charge pump and passive loop filter to reduce the PLL reference spurs.