3: Setting up PMUs and PGUs in Clarius Model 4200A-SCS Pulse Card (PGU and PMU)
3-38 4200A-PMU-900-01 Rev. B March 2023
Since the interconnect and the DUT always have some capacitance, it is best to charge up this
capacitance as quickly as possible. This can be done by allowing the maximum amount of current to
flow into the capacitor during charging. This may cause an overflow for the measure range during
transitions, especially on the lower RPM measure ranges. Note that the measurement range cannot
be changed within a pulse, so a single measure range must be used for the entire pulse.
If the PMU or RPM was current limited to the measure range, the charging rate would require a longer
time to reach a settled signal. With the maximum current available at all measure ranges, the signal
will settle as fast as possible, allowing for a good dc-like current measurement using the shortest
possible pulse. This is especially important at the lower current measure ranges, when the settled
part of the pulse may have a signal level in the nA (or single μA) value, but the charging current is
possibly tens of μA (or mA, respectively).
See PMU capacitive charging/discharging effects (on page 3-35
) for information on the cause of the
capacitive charging effect and how to work around it.
4220-PGU and 4225-PMU output limitations
In addition to the maximum output of the PMU and PGU instrument cards (see DUT resistance
determines pulse voltage across DUT (on page 4-17)), the pulse instrument cards also have a limit for
the number of large amplitude pulse transitions within a period. The 4200A-SCS system enforces
limits on the quantity and amplitude of waveforms that the 4220-PGU and 4225-PMU may generate.
A test exceeding these internal limits generates error code -830. To fix this problem, increase the
pulse period, decrease the voltage amplitude, or both. For information on the pulse default values,
see the pulse_init LPT command description.
Configure the PGU, PMU, and RPM using tests
To configure and control the PGU, a user test module (UTM) is needed. You can also use UTMs to
configure and control the PMU and RPM preamplifier. For UTM programming, see “LPT commands
for PGUs and PMUs” in Model 4200A-SCS LPT Library Programming.
You can use interactive test modules (ITMs) to configure and control a PMU and RPM preamplifier.
Refer to “Configure a simple test” in Model 4200A-SCS Clarius User's Manual for information on
configuring an ITM for the PMU.
An ITM automatically controls the RPM based on the type of test (pulse, CV, SMU). RPM switching
can only be controlled using the rpm_config LPT function in a UTM. For details, refer to
Using the
RPM as a switch (on page 2-9).
For automatic switching of the RPM in ITMs, the RPM must already have all instrument cabling
connected and recognized by the system. Information on performing this update is in “Update the
RPM configuration” in Model 4200A-SCS Setup and Maintenance.
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