Scientific 5000 Series, Manual

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APPENDIX F
MODEL 5000 SERIES MANUAL
Version 1.23
13-15
Appendix F
Device Test Notes
Transistor V
BEON
and h
FE
The 5000 Series Tester Models 5000E and 5300HX execute most tests using the
single test measure method. V
BEON
and h
FE
tests are performed in the single test
method by applying drive to the base of the DUT and monitoring the resulting
collector current that is used as feedback. This eliminates the problem of setting I
B
to
a value that will produce the specified I
C
. I
B
is not directly controlled, but is the result
of forcing the I
C
to its programmed value and the resulting V
BE
or I
B
is measured to
obtain a value in a single application of the stimulus. Total test time for mid-range
current values is less than 10 milliseconds.
Transistor I
CEO
Test
An I
CEO
test is complicated by the fact that a collector current is generated when
voltage is applied to the collector, even though the base is open. This effect is most
pronounced in power transistors.
This charging current can be high enough to simulate an overload condition that the
system interprets as a device failure. A charging range is pulled in during the voltage
rise period to minimize this effect. However, the resulting apparent measurement
can be much higher than the true I
CEO
value and will probably occur at a decade
boundary; i.e., 9.9
μA, 99.9μA, 0.99mA, etc.
This condition can be eliminated if an I
CER
, I
CES
or I
CEV
test is used. The base lead
cannot float under these conditions and the test result is consistent and accurate.
Most power transistor specifications list at least one of these tests.
These tests program the same as an I
CEO
test except the base to emitter (R
BE
) is tied
through a load, shorted, or reverse biased.
Transistor BV
CE
Test
13.1.1 BV
CEO
BV
CEO
or V
(BR)CEO
is defined as the breakdown voltage between the collector and
emitter terminals with the base open. MIL-STD-750C, Method 3011.1 defines this
parameter to be that voltage at which the specified collector current flows. It is
obviously necessary that the specified current level be reached in order to measure
the breakdown voltage.
The 5000 Series tester performs this test by applying a current drive and measuring
the resulting collector to emitter breakdown voltage. To minimize device heating, this
test is run at 300
μS for collector currents above 10mA, as most vendors specify. In
addition, a programmable base pulse can be applied to help ease the device into
breakdown as described below. Alternatively, an external capacitor can be attached
form the collector to base at the 5000 Series Tester front panel ANET terminals with
Use I
CER
, I
CES
or I
CEV
in place of I
CEO
when possible.