Fig. 6.20 shows the oscillator output voltage simulated by SPICE. Compared with Fig. 6.16 the output voltage increases faster to its final value.
Similar to the result obtained by MINIMOS-NT the oscillation starts with a frequency of 171 MHz and decreases to its steady state value within the first 25 ns as can be seen from Fig. 6.21. However, the steady state frequency of 101 MHz is considerably lower than the frequency obtained from simulations performed by MINIMOS-NT.
The CPU time consumed for this simulation on the same computer as for the device simulation was below 1 s. The number of unknowns for this circuit was 50 and only 99 floating-point operations were necessary to solve one linear equation system.
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