Section 4: Theory of operation
Model 2651A High Power System SourceMeter® Instrument Reference Manual
4-22
2651A-901-01 Rev. A / March 2011
Figure 82: Pulse rise and fall times
Pulse level
Bias level
Start t
on
Start t
off
90%
10%
t
Latency
on
t
off
10%
Rise
time
Trigger
Pulse
Period
Fall
time
(Pulse width)
Cable specifications and connection configuration
Cable length, as well as capacitance and inductance in both the cabling and the test fixture, can affect
pulse performance. See
(on page 4-20) for pulse related considerations that
may affect your connection scheme.
Range and pulse setting
Each range has different specifications for transient response settling times or pulse rise times (and
source output settling times). This causes different rise and fall time characteristics depending on the
set range. Refer to the Model 2651A specifications for details.
In addition, pulse performance is dependent on the pulse setting as a percent of full scale. For
example, a 1 A pulse on the 10 A range (which is 10%) will perform differently than a 10 A pulse on
the 10 A range (which is full scale).
Load and operating mode
Settling times for the current source will vary with the resistive load applied, as does the transient
response times will vary with the voltage source range. In addition to the load, the times will vary
dependent on whether the source-measure unit (SMU) is configured as a voltage source or a current
source.
