4-4
SeCTIon 4
FET Tests
4.4.2 example Program 10:
Transconductance vs.
Gate Voltage Test
Use Program 10 to generate a typical g
fs
vs . V
GS
plot as well as a
g
fs
vs . I
D
.
With the power off, connect a dual-channel System Source-
1 .
Meter instrument to the computer’s IEEE-488 interface .
Connect the test fixture to both units using appropriate
2 .
cables .
Turn on the instrument and allow the unit to warm up for two
3 .
hours for rated accuracy .
Turn on the computer and start Test Script Builder (TSB) . Once
4 .
the program has started, open a session by connecting to the
instrument . For details on how to use TSB, see the Series 2600
Reference Manual .
You can simply copy and paste the code from Appendix A in
5 .
this guide into the TSB script editing window (
Program 10
),
manually enter the code from the appendix, or import the TSP
file ‘
Transconductance.tsp
’ after downloading it to your PC .
If your computer is currently connected to the Internet, you
can click on this link to begin downloading:
http://www.
keithley.com/data?asset=50916
.
Install an N-channel FET such as an SD210 in the appropriate
6 .
transistor socket of the test fixture .
Now, we must send the code to the instrument . The simplest
7 .
method is to right-click in the open script window of TSB, and
select ‘
Run as TSP file
’ . This will compile the code and place
it in the volatile run-time memory of the instrument . To store
the program in non-volatile memory, see the “TSP Program-
ming Fundamentals” section of the Series 2600 Reference
Manual .
Once the code has been placed in the instrument run-time
8 .
memory, we can run it at any time simply by calling the func-
tion ‘
Transconductance()
’ . This can be done by typing
the text ‘
Transconductance()
’ after the active prompt in
the Instrument Console line of TSB .
In the program ‘
9 .
Transconductance.tsp
’, the function
Transconductance(vgsstart, vgsstop,
vgssteps, vdsbias)
is created .
vgsstart
•
represents the initial voltage value in the
gate-source V
GS
sweep
vgsstop
•
represents the final voltage value in the gate-
source V
GS
sweep
vgssteps
•
represents the number of steps in the sweep
vdsbias
•
represents the voltage value applied to the
drain-source terminal of the FET
If these values are left blank, the function will use the default
values given to the variables, but you can specify each variable
value by simply sending a number that is in-range in the func-
tion call . As an example, if you wanted to have the start volt-
ages for V
GS
sweeps be 1V, the stop value be 11V, the number
of steps be 20, and the V
DS
value as 5V, you would send
Transconductance(1, 11, 20, 5)
to the instrument .
The sources will be zeroed and then enabled . The instrument
10 .
will apply V
DS
and execute a sweep of V
GS
values between
0V and 5V using 100 steps . At each increment, I
D
will be
measured .
I
V
I
V
Series 2600
System
SourceMeter
Channel A
Sources V
DS
,
Measures I
D
Series 2600
System
SourceMeter
Channel B
Sweeps V
GS
V
DS
V
GS
Test
Fixture
FET
Under Test
Output HI
Output HI
Output LO
Output LO
I
D
Figure 4-3. Configuration for transductance tests
Summary of Contents for Series 2600
Page 5: ......
Page 7: ......
Page 17: ...2 8 Section 2 Two terminal Device Tests...
Page 39: ...4 10 Section 4 FET Tests...
Page 53: ...6 4 Section 6 High Power Tests...
Page 130: ...A 77 Appendix A Scripts BJT_Comm_Emit_Vsb...
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