Keithley 2520, User Manual, Page: 109 / 329

7-4 Sweep Operation Model 2520 User’s Manual
Thus, the five log steps for this sweep are 0, 0.25, 0.50, 0.75, and 1.00mA. The actual cur-
rent source levels at these points are listed in
Table 7-1 (the current level is the anti-log of
the log step).
When this sweep is triggered to start, the output will go to the start source current level
(1mA) and sweep through the symmetrical log points. The time duration at each step is
determined by the time it takes to perform the measurement, which includes the pulse
delay time.
Custom sweep
This sweep type lets you configure a customized sweep (via remote only). Programmable
sweep list parameters include the number of measurement points in the sweep, the current
source level at each point, pulse width, and pulse delay.
Figure 7-3 shows an example of a custom sweep. When this sweep is started, the output
goes to the first current level in the sweep after the delay period. The pulse period and time
between pulses is determined by the programmed pulse and delay parameters. The sweep
will continue through the points in the order they were programmed and stop after the last
current point.
The size of the current list determines the custom sweep size. Normally, the pulse width
list and delay list should be the same size as the current list. However, if the pulse width
and/or pulse delay list is shorter than the current list, the last pulse width and/or delay
point will be used for all subsequent current values.
Figure 7-3
Custom pulse sweep
Table 7-1
Logarithmic sweep points
Measure point Log step Current level (mA)
Point 1
Point 2
Point 3
Point 4
Point 5 0
0.25
0.50
0.75
1.0 1
1.7783
3.1623
5.6234
10
Pulse 1
Pulse 2
Pulse 3
Width
Width
Width
Delay Delay Delay