3: Setting up PMUs and PGUs in Clarius Model 4200A-SCS Pulse Card (PGU and PMU)
3-24 4200A-PMU-900-01 Rev. B March 2023
Settling time is measured from the 90 percent point on the rising edge to the point where the pulse
level remains in the accuracy band, as shown in the following figure.
Figure 52: Settling time
PMU minimum settling times versus current measure range
The PMU and RPM current measure ranges require time to reach a settled value. The amount of
settling time that is required increases for the lower current measure ranges.
You can set the pulse timing parameters (pulse width, rise, and fall) to any valid values and are
independent from the recommended minimum timing values required to obtain settled readings. If the
chosen pulse width is too narrow, the lower current measure ranges are not available. The timing of
the pulse top and pulse base are used, along with the minimum timing in the chart to determine which
current measure ranges are available.
In ITMs, when you modify the PMU timing settings in the Advanced Test Settings, if you make a pulse
timing change that affects the measure range of a PMU channel, a message noting the unavailable
ranges is displayed. You should check the recommended pulse width and period for the measure
ranges noted in the message. When setting the PMU force measure options, if a timing parameter
prevents use of one or more PMU or RPM measure ranges, the note in the center of the window turns
red and lists the unavailable ranges. Access the PMU force measure options by selecting the FORCE
MEASURE button.
The Typical Minimum Timing Recommendations dialog shows the recommended minimum pulse
widths and transition (rise and fall) times for each current measurement range. These times are the
minimum time necessary for the PMU, or PMU with RPM, to reach a settled value (into an open).
Additional time must be entered to account for DUT settling time, usually due to RC effects.
If you need to use autoranging with the RPM, note that the appropriate minimum timing values are
the first row in the table. Note that the pulse timing values are not altered during the test, unless a
time sweep or time step is configured. This means that the pulse width is not changed as the
measure range changes. When using autoranging or limited autoranging, choose the recommended
minimum timing values for the lowest chosen measure range.
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