Model 4200A-SCS Parameter Analyzer Reference Manual
Section 5: Pulse measure and pulse generator units
4200A-901-01 Rev. C / February 2017
5-43
This capacitive charging current is primarily a measurement artifact, as the current does not flow
through the DUT. Note that if a spot mean is taken during the settled portion of the pulse, then this
charging does affect the spot mean measurement.
The next two figures show the waveforms and setup for a pulse test on a resistor DUT and illustrates
a configuration to eliminate this artifact. The next figure shows that the channel 2 current waveform
does not have this current charging artifact. This is because channel 2 is not pulsing, so dV/dt = 0.
Using channel 2 in this configuration is sometimes called "low-side measurement." This measurement
approach is useful when analysis of the current signal pulse transitions is required.
Figure 180: Low-side measurement waveforms
The previous figure shows the current waveforms for both PMU channel 1 (high side) and channel 2
(low side) current measurements. Note that channel 2 does not show the capacitive charging effects
and that the channel 2 current measurement is negative because current is flowing into channel 2.
Figure 181: Setup for low-side measurement
In the previous figure, the voltage pulse is applied by channel 1; channel 2 does not pulse. Therefore,
there is no dV/dt, and there are no charging or discharging currents during the pulse transition. The
red arrows show charging and DUT current for channel 1. The green arrow shows the DUT current
only for channel 2.
