Hi, this problem shows up in v24 and v25, in the windows version and the CYGWIN version.
When monitoring the current consumption of a ring oscillator, there is a wild +/- current swing for the first 1.5 nanoseconds UNTIL an unconnected voltage pulse source changes output levels. At that time the ringing instantly stops. The output of the voltage source is floating and is not connected to any of the circuit except for node "0" (gnd).
If I do the same analysis without UIC, the current is shown as a fairly stable 0.2 ma or so.
When I run the same netlist in LTCspice I don't see the influence of the voltage pulse source.
I am a complete SPICE newbie, so I may be messing something up or this is known behaviour. In case it is a real bug I thought you fine folks would like to know about it.
The ring oscillator and 50nm MOS models are from Jacob Baker's EXCELLENT book, CMOS Circuit Design, Layout, and Simulation.
Cheers, Kevin Szabo