The proposed stimulator output stage circuit has been
simulated in Cadence using the X-FAB 1μm SOI-CMOS
process technology with a 5V power supply. Fig. 5 shows a
snapshot of the simulation current waveform through a load
with an impedance of 2kΩ load (post-layout simulation). The
charge generated in the active cathodic phase is neutralized by
the charge generated in the passive anodic phase. The
summation of the two 50ns high-frequency currents produces
a long cathodic phase (1ms long). The glitches evident on the
load current are due to switching delays. However, these
glitches only last a fraction of the active cathodic phase and
are thus not considered a problem at all. The initial amplitude
of the passive anodic phase was limited to 10% of the cathodic
amplitude (which is a reasonable ratio in practice).