2606B System SourceMeter® Instrument Reference Manual
Section 4: Theory of operation
2606B-901-01 Rev. B / May 2018
4-19
Effects of load on current source settling time
The settling time of the source-measure unit (SMU) can be influenced by the impedance of the device
under test (DUT) in several ways. One influence is caused by an interaction between the impedances
of the SMU current source feedback element and the DUT. This interaction can cause a reduction in
the bandwidth of the SMU. This reduction causes an increase in the settling time of the current
source.
There is a maximum DUT impedance for each current source range for which the specified current
settling times are maintained. The following table lists the DUT impedances for each of these current
source ranges. For latest specifications, go to
. The settling time on a current source
range can increase significantly when measuring DUTs that have an impedance that is higher than
the maximum DUT impedance listed below.
Maximum DUT impedances for specified settling time
performance
Range
SMU feedback
impedance
Maximum DUT
impedance
100 nA
40
MΩ
20
MΩ
1 µA
1.2
MΩ
600
kΩ
10 µA
400
kΩ
200
kΩ
100 µA
12
kΩ
6
kΩ
1 mA
4
kΩ
2
kΩ
10 mA
120
Ω
60
Ω
100 mA
40
Ω
20
Ω
1 A
1
Ω
6
Ω
3 A
0.3 Ω
1.5
Ω
Creating pulses with the 2606B
Although the 2606B is not a pulse generator, you can create pulses by programming the 2606B to
output a DC value and then return to an idle level. For information on how to create pulses, refer to
Using the remote trigger model
(on page 3-33).
Pulse rise and fall times
Although the 2606B can create pulses, it is not a pulse generator (pulse rise times are not
programmable).
The pulse rise time is the time it takes a pulse to go from 10% to 90% of the pulse's maximum value.
Pulse fall time is similar but on the pulse's trailing edge. For the 2606B, pulse rise and fall times can
vary depending on the following factors:
•
Cable specifications and connection configuration
•
(on page 4-20)
•
(on page 4-20)
•
Compliance limit settings (for details, see
(on page 2-35))