Tektronix KEITHLEY SourceMeter 2606B Reference Manual page 154

Model 2606B System SourceMeter® Instrument Reference Manual
Source settling times
Each 2606B source-measure unit (SMU) can drive up to 50 µF of a capacitance in high-capacitance
mode. To accomplish this, the speed of the 2606B SMU is reduced. Source settling times increase
when high-capacitance mode is enabled. The following table compares examples of the differences in
source settling times between normal and high-capacitance modes.
Source settling times
Range
100 mV
1 V
6 V
20 V
In high-capacitance mode, the frequency compensation capacitance across the measure range
resistors increases. This increase causes longer settling times on some current measure ranges. The
same range elements that are used to measure current are used to source current. As a result, the
current limit response times respond in a similar manner. Examples of the differences in source
settling times are shown in the following table.
Current measure and source settling times
Current measure range
1 A to 3 A
100 mA
10 mA
1 mA
100 µA
10 µA
1 µA
When high-capacitance mode is enabled, the amount of time to change the current measure range
increases for each SMU. The current measure range and the current limit range are locked together.
Setting the current limit automatically updates the measure range.
Adjusting the voltage source
When driving large capacitive loads with high-capacitance mode enabled, the response time may be
lengthened by the current limit. For example, see the table titled "Current measure and source settling
times" in Understanding source settling times
10 μs with a 1 A limit and the limit is set to 100 nA, the charging time is 100 seconds, as shown in the
following equation.
2606B-901-01 Rev. C November 2021
Normal mode High-capacitance mode
50 µs 200 µs
50 µs 200 µs
100 µs 200 µs
150 µs 7,000 µs
Section 5: Sourcing and measuring
Normal mode High capacitance mode (typical)
(typical)
80 µs 120 µs (R
100 µs 100 µs
80 µs 100 µs
100 µs 3,000 µs
150 µs 3,000 µs
500 µs 230,000 µs
2,000 µs 230,000 µs
(on page 5-53). If a 1 μF capacitor charges to 10 V in
> 2 Ω)
LOAD
5-53