ASTM F769-00

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:F 769–00
Standard Test Method for
Measuring Transistor and Diode Leakage Currents
This standard is issued under the fixed designation F 769; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 4.2 Ionizing radiation, that is, space radiation or gamma
radiation, may have a long term (permanent) effect on the
1.1 This test method covers the measurement of leakage
leakage current. Thus, the total dose to which a transistor or
currents of transistors and diodes. Electronic devices exposed
diode has been exposed may have a significant effect on the
to ionizing radiation may show increases in leakage current as
leakage current and hence the biasing and power supply
the accumlated total dose rises.
stagility and functioning. This must be considered during
1.2 These procedures are intended for the measurement of
−11 −3
design, device selection and production line part device accep-
currents in the range from 10 to 10 A.
tance.
1.3 This test method may be used with either a virtual-
ground current meter or a resistance-shunt current meter.
5. Interferences
1.4 The values stated in Internationl System of Units (SI)
5.1 Noise generated by thermal agitation in the various
are to be regarded as standard. No other units of measurement
resistancesinthetestcircuitsetsanultimatelimitofinstrument
are included in this test method.
resolution.Thenoisecurrentgeneratedinacurrentmetershunt
1.5 This standard does not purport to address all of the
resistor is proportional to the inverse square root of the
safety concerns, if any, associated with its use. It is the
resistance, so a high shunt resistance value is desirable.
responsibility of the user of this standard to establish appro-
5.2 Other sources of noise are a–c signals propagating
priate safety and health practices and determine the applica-
throughthepowersupplyorimposedonthetestleads.Ameter
bility of regulatory limitations prior to use.
with a high a–c rejection ratio and with high common mode
2. Terminology rejection ratio will be less sensitive to such forms of noise. A
shielded test fixture may be required for proper measurement
2.1 Definitions:
of low currents.
2.1.1 resistance-shunt meter—a meter that determines cur-
5.3 All components associated with very high resistance
rent by measuring the voltage generated across shunt resistors
circuitry should be mechanically rigid. Movement of a coaxial
by the current.
cable can produce piezoelectric and triboelectric effects in the
2.1.2 virtual-ground meter—ameteremployingfeedbackto
cable which result in voltages across the current meter inputs.
the amplifier in such a way as to make the meter input appear
5.4 Whenworkingwithahighresistancesource,allleakage
to be at ground potential.
paths must be high in comparison to the circuit resistance.
3. Summary of Test Method Phenolic or rubber insulation, for example, may have a
resistanceofonly10 V,causinglargeerrorsinmeasurements
3.1 Ajunctionwhoseleakageistobedeterminedisreverse-
with circuit resistances of greater than 10 V.
biased with a power supply.Acurrent meter is placed in series
5.5 Circuits employing a feedback picoammeter can have
with the junction and the appropriate range is selected on the
measurement errors which result from offset current, offset
meter. The current is read directly from the meter readout.
voltage, drift, and time constants in the amplifier. Amplifier
4. Significance and Use
time constants are of particular importance whenever the
annealing rate of an irradiated device approaches the sampling
4.1 Knowledge of diode and transistor leakage currents is
rate of the current meter.
very important to the circuit designer. Proper transistor biasing
5.6 Thevoltagedropacrossaresistance-shunttypeammeter
depends on accurate leakage current data.
for a given current varies with the range selected. Therefore, a
range which gives maximum meter resolution will also intro-
This test method is under the jurisdiction of ASTM Committee F-1 on
duce maximum voltage drop error. An excellent way of
Electronicsand is the direct responsibility of Subcommittee F01.11 on Quality and
determining the input resistance of an ammeter is by direct
Hardness Assurance.
measurement using a transistor curve tracer.Arange should be
Current edition approved June 10, 2000. Published August 2000. Originally
published as F769–82. Last previous edition F769–95.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
F 769
7. Calibration
7.1 Adjustpowersupplytothevoltagetobeusedinbiasing
the junction. Measure voltage with voltmeter.
7.2 Select a resistor such that R= V / I .
BIAS LEAK(EXPECTED)
7.3 Place the resistor in the socket and measure the current.
Verify that the current is within I 6 (Resistor
LEAK(EXPECTED)
Tolerance + Voltmeter Accuracy + Electrometer or Current
FIG. 1 Unshielded Test Fixture
Meter Accuracy).
7.4 Remove resistor from socket and measure the current.
selectedwhichhasanassociatedresistancelessthan1%ofthe
Verify that the open-socket current is less than 1% of the
equivalent resistance (bias voltage/leakage current) of the test
expected leakage current value for currents in the range from
device. −10 −3
10 to10 Aandlessthan6%forcurrentsintherangeof
5.7 Care must be taken to keep the test device and test −11
10 A.
fixture free from co
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