Keithley Series 2600 User Manual

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3-9

SECTION 3

Bipolar Transistor Tests

To store the program in non-volatile memory, see the “TSP

Programming Fundamentals” section of the Series 2600 Refer-

ence 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 ‘DC_Gain_Search_Fast()’. This can be done by typing

the text ‘

DC _ Gain _ Search _ Fast()

’ after the active

prompt in the Instrument Console line of TSB.

In the program ‘9. DC_Gain_Search_Fast.tsp’, the function

DC _ Gain _ Search _ Fast(vcesource, istart,

istop, isteps)

is created.

vcesource

• represents the voltage value on the

collector-emitter of the transistor

istart

• represents the start value for the base current

sweep

istop

• represents the stop value for the base current

sweep

isteps

• represents the number of steps in the base

current sweep

If these values are left blank, the function will use the default

values given to the variables, but you can specify each vari-

able value by simply sending a number that is in-range in

the function call. As an example, if you wanted to have the

collector-emitter voltage (V

) be 2.5V, the base current sweep

start value at 10nA, the base current sweep stop value at

100nA, and the number of steps to be 10, you would send

DC _ Gain _ Search _ Fast(2.5,10E-9, 100E-9,

10)

to the instrument.

The sources will be enabled, and the collector current of the 10.

device will be measured.

Once the sweep has been completed, the data (I11.

, I

, and ß)

will be presented in the Instrument Console window of TSB.

Note that the program reverses the polarity of the emitter cur-

rents in order to display true polarity.

3.5.10 Program 6B Description

Initially, both units are returned to default conditions. SMUB,

which sources V

and measures I

, is set up as follows:

Source V•

1mA compliance, autorange measure•

Remote sense•

vcesource

• : –10V

SMUA, which sources I

, is conﬁgured as follows:

Source I•

Local sense•

11V compliance, autorange•

istart

• : –1mA

istop

• : –10mA

isteps

• : 10

10ms delay•

Staircase sweep mode•

Both SMU outputs are then zeroed and enabled. Next, SMUB

sources V

and SMUA begins the current sweep on the emitter

current (I

) from istart to istop in isteps. At each point in the

sweep, SMUB measures the base current (I

). Upon completion of

the sweep, the current gain (ß) is calculated and the data (I

, I

and ß ) is printed to the Instrument Console of the TSB.

3.5.11 Example Program 7:

AC Current Gain

NOTE

For the sake of simplicity, this program does not include

the iterative search algorithm included in Program 6A.

To test at a speciﬁc IC value, ﬁrst use Program 6A to

determine the base current at that target value, and

enter I

values slightly higher and lower when prompted

to do so in Program 7.

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 7),

manually enter the code from the appendix, or import the TSP

ﬁle ‘AC_Gain_.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=50931.

Install a small-signal NPN silicon transistor such as a 2N5089 6.

in the appropriate 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.

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Keithley Series 2600 Specifications

General

Model	Series 2600
Measurement Functions	Voltage, Current, Resistance, Power
Resolution	Up to 6.5 digits
Current Source Range	Up to 10A
Communication Interfaces	GPIB, USB
Applications	Semiconductor testing
Category	Source Measure Unit (SMU)
Channels	Single or Dual Channel (varies by model)