Monolithic CMOS voltage-controlled oscillator (VCO) design emerged during the 1990's as a response to the cost/performance demands of wireless and networking applications. The stringent specifications imposed on VCOs (GHz frequencies, low noise, low power, low cost, stability across process, voltage, temperature conditions) and the characteristics of nanometer CMOS devices require complex circuit implementations that are inherently highly nonlinear. Traditional RF simulation tools often cannot achieve periodic steady-state (PSS) convergence without model simplification (for example, removing the buffer and bias circuitry). If they do converge, their runtime is often excessive and they may produce phase noise results that can be proven to be inaccurate.

Designers often use crystal oscillators (XOs) in many clocking systems. XOs have a high quality factor (high-Q) and are highly nonlinear causing traditional RF simulators to struggle with PSS convergence and accuracy on XO circuits.

RF FastSPICE utilizes a Berkeley Design Automation proprietary nonlinear engine to deliver dramatically improved PSS convergence and noise accuracy for highly nonlinear, nanometer CMOS VCOs and XOs.

The table below lists customer VCO and XO circuits for which Analog FastSPICE and RF FastSPICE delivered full SPICE accuracy at least 5X faster.