A Wide Frequency Range Low Jitter Integer PLL with Switch and Inverter Based CP in 0.18 μm CMOS Technology

摘要

This paper aims at designing a digital approach based low jitter, smaller area and wide frequency range phase locked loop (PLL) to reduce the design efforts and power which can be used in System-on-chip applications for operating frequency in the range of 0.025-1.6 GHz. The low power, scalable and compact charge pump is proposed which reduces the overall power consumption and area of proposed PLL. A frequency phase detector (PFD) based on inverters and tri-state buffers have been proposed for the PLL. It is fast which improves the locking time of PLL. Also, pseudo-differential voltage controlled oscillator (VCO) is designed with CMOS inverter gates. The inverters are used as phase interpolator to maintain the phase difference of 180 degrees between two outputs of VCO. Also, the inverters are used as variable capacitors to vary the frequency of proposed VCO with control voltage. It demonstrates the good phase noise performance enabling proposed PLL to have low jitter and wide frequency range. All the major blocks like PFD, charge pump and VCO are designed using digital gate methodology thus saving area and power and also reduce design efforts. Also, these digitally designed blocks enable the PLL to have low jitter small area and wide range. The proposed PLL is designed in a 0.18-mu m CMOS technology with supply voltage of 1.8 V. The output clocks with cycle-to-cycle jitter of 2.13 ps at 1.6 GHz. The phase noise of VCO is -137 dBc/Hz at an offset of 100 MHz and total power consumed by the proposed PLL is 2.63 mW at 1.6 GHz.