Model 2657A High Power System SourceMeter® Instrument Reference Manual
Section 3: Functions and features
2657A-901-01 Rev. B/December 2012
3-65
Understanding the capacitor
Based on the capacitor's dielectric absorption performance, the settling time may change.
Tantalum or electrolytic capacitors are well known for long dielectric absorption settling times.
Film capacitors and ceramics perform better, with NPO/COG dielectric ceramics yielding the best
settling response.
Charging the capacitor and taking readings
The following steps outline the procedure to charge and read a capacitor in high-capacitance mode:
1. Set the current limit to a value that is higher than will be used for the measurement (for example,
if measuring at 10
μ
A, set the initial current limit to 100 mA).
2. After the capacitor charges, lower the current limit and measure range to obtain the current
measurement.
Enabling high-capacitance mode
Before enabling high-capacitance mode, note the following:
•
It is important to read the previous section to understand the impact of high-capacitance mode.
•
Test the DUT and the capacitor to determine the best current limit and range of output voltages.
•
The settling times can vary based on the DUT. It is important to test the limits of the DUT before you
use high-capacitance mode.
•
Failure to test the DUT for the appropriate current limit and output voltages can result in damage to or
destruction of the DUT.
•
For optimal performance, do not continuously switch between normal mode and high-capacitance
mode.
•
Before you charge the capacitor, start with 0 (zero) voltage across the capacitor.
•
When high-capacitance mode is enabled, a minimum load capacitance of 100 nF is recommended. In
the absence of this minimum load capacitance, overshoot and/or ringing may occur.
Front panel
To enable high-capacitance mode from the front panel:
1. Press
the
CONFIG
key and then select
SRC
>
HIGHC-MODE
.
2. Select
ENABLE
.
3. Push
the
ENTER
key to enable high-capacitance mode.
4. Press
the
EXIT (LOCAL)
key to back out of the menu structure.
NOTE
Summary of Contents for 2657A
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