Capacitance Example - Keithley 595 Instruction Manual

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25.4 Capacitance Example
The following is an example capacitance measurement to
aquaint the user with typical measurement techniques. In
this particular example, the device under test (D.UX) has
a value of about 5OOpE
The initial measurement configuration is power OFF, with
connections as described in paragraph 2.5.3. The circuit is
broken at the capacitor under test (i.e., the probe is lifted
from the wafer).
Follow the steps outlined below to make a capacitance
measurement. The first column indicates what button
should be pressed; the second column shows what will be
displayed on the Model 595, and the last column describes
the results of the action taken.
Button Press
Display
Remarks
1. POWER
IT.
I.O.
0.000
2. ZERO CHECK
3. RANGE V
4. SUPPRESS
5. ZERO CHECK
6. (Connect capacitance in fixture)
7. ZERO CJFIECK
8. SHIFT, then STORE Co
O.OOT
.ool2=
.oooo
.oooo
.4562*
.4562*
9. UC, -~
1.0000*
10. SHIFT, then Q/t .oooo*
Il. CAPACITANCE*
1.0000~
IiF
IIF
Memow test (RAM)
Memo6 test (ROMj
2018 capacitance range, ZERO CHECKS on, square
wave.
ZERO CHFCK off, measuring stray capacitance of
fixture.
Go to range of desired resolution (D.U.T. will be
about 500pF).
SUFT'RESS on, stray value will be subtracted from
all readings.
ZERO .CHECK on while connecting device.
Display is value of D.UX (minus fixture strays).
ZERO CHECK off to resume measurement.
This value is stored as Co for normalization of
capacitance.
The measured capacitance is normalized to C&
The magnitude of current through the D.U.T at the
time of each capacitance measurement (i.e., after
delay time). Note: suppress and Co apply only to
the capacitance measurement, not to Q/t.
Return to normalized capacitance display.
12. UC,
.4562* nF
UC0 off.
* This value depends on the capacitor under test, any strays present, etc.
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