Delays are on by default for the 2634B, 2635B, and 2636B. Delays are off by default for the 2601B,
2602B, 2604B, 2611B, 2612B, and 2614B but can be enabled.
You can manipulate both the analog filter and the default delays to produce faster response times.
Turn off the analog filter to yield faster settling times. Control the default delays by using the delay
factor multiplier. The default value for delay factor multiplier is 1.0, but adjusting it to other values
result in either a faster or slower response. For example, increasing the delay factor to 1.3 accounts
for settling to 0.01 percent of the final value. The commands to manipulate the delay factor and
analog filter are shown in the following topics.
Programming example for controlling settling time delay
The following code provides measure delay examples for controlling settling time delay of SMU
channel A. You can use the delay factor to apply a multiplier when smuX.measure.delay is set to
smuX.DELAY_AUTO. Setting the delay factor above 1.0 increases the delay; a value below 1.0
decreases the delay. Setting this value to 0.0 disables delays when autodelay is on.
-- Turn off measure delay (default setting is smua.DELAY_AUTO).
smua.measure.delay = 0
-- Set measure delay for all ranges to Y in seconds.
smua.measure.delay = Y
-- Adjust the delay factor.
smua.measure.delayfactor = 1.0
Programming example for controlling analog filter (2634B, 2635B,
and 2636B only)
The following code is an example of a measure delay that controls the analog filter of SMU channel A:
-- Default setting (analog filter on).
smua.measure.analogfilter = 1
This filter is only active when the current measure range is 1 nA/100 pA. Setting the attribute to zero
(0) disables the filter.
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 results in an increase in the settling time of the
current source.