Research And Design Of Radiation Hardened CMOS Frequency Synthesizer

With the rapid development of aerospace technology,more and more electrical systems work in radiation environment of aerospace.Frequency synthesizer is a core component of the communication system on spacecraft,and is exposed in the radiation environment,so it will face huge threatens of radiation effects such as single event transient（SET） effect and will result in frequency or phase shift,or even result in suspension of oscillation.It may lead to the disruption of communication,which seriously threatens the reliability of the spacecraft.Therefore,it is very important to research radiation harden technologies of frequency synthesizer.So a radiation hardened by design frequency synthesizer is researched and designed in SMIC 0.13μm CMOS process in this thesis.The main works include:Firstly,a high power supply rejection ratio（PSRR） high-order temperature-compensated bandgap reference（BGR） is designed by adopting subthreshold MOS field-effect transistors,the piecewise-curvature temperature-compensated technique and the pre-regulator technique.Simulation results show that the temperature coefficient（TC）of the designed subthreshold MOS BGR is 1.38×10^-6/℃ in the range from-40℃ to 125℃,and it achieves the PSRR of-104.54dB at 10 Hz with a power supply voltage of1.2 V.Secondly,a frequency synthesizer is designed by adopting the improved charge pump（CP） with self-cascode current mirror,complementary cross-coupled LC-tank voltage controlled oscillator（LC-tank VCO）,improved triple-state phase frequency detector（PFD） and a 32 frequency divider in this thesis.Simulation results show that the frequency synthesizer has a 2.4GHz output frequency when input frequency is 75 MHz,and it can be locked in 1.8μs.Thirdly,SET sensitivity analysis of every submodule has been set by using the double exponential current pulse model to inject in each submodule of frequency synthesizer.Simulation data of the different incident nodes and different energy shows that every submodule will generate different level SET responses,and the output node of CP is most susceptible to SET effect.Finally,a radiation hardened by design（RHBD） frequency synthesizer is designed in this thesis.A radiation-hardened CP is designed by employing resistance isolation,voltage monitoring and current compensation techniques.Radiation-hardened LC-tank VCO is designed by adopting RC filter technique.Radiation-hardened PFD and divider are designed by implementing the triple module redundancy technique.Simulation results show that the control voltage deviation has decreased by 96.6%,recovery time has been inproved by 47.9%and the measured max output phase displacement has decreased by 95.5%in the SET response.It can be concluded that the designed radiation hardened frequency synthesizer has decrease SET sensitivity effectively,and can work well in radiation environment.