差分压控振荡器中单粒子瞬变的研究

Research on Single-event Transients in Differential Voltage-controlled Oscillators

压控振荡器(VCO)是锁相环(PLL)中对于单粒子瞬变(SET)最为敏感的部件之一。基于180nm体硅CMOS工艺设计了一款经典的对称负载结构差分VCO电路,并利用电流源表征单粒子效应中电荷沉积和收集的过程,模拟了VCO电路的SET响应。模拟和分析表明,SET响应不仅取决于入射能量、振荡频率,还受到轰击时刻的制约,不同轰击时刻产生的最大相位差可以相差300°以上。此外,偏置电路某些结点最为敏感,可以放大SET的影响,导致时钟失效长达7个周期。

The responses of voltage-controlled oscillators （VCOs） to single-event transients （SETs） were investigated. A classic differential VCO with symmetricall loads was implemented in a 180nm bulk CMOS process. Modeling the charge deposition and collection from ion strikes as a current source, the transient SET responses of this VCO were achieved by circuit-level simulation. Simulations and analysis indicated SET responses were not only dependent on incident energy and the frequency of oscillation, but also dependent on striking time, which can increase the phase displacement by up to 300 degrees. Additionally, some nodes in the bias generation circuit are most sensitive to SET. Strikes in these nodes were amplified and resulted in an approximate 7 clock cycles distortion.