ASTM F632-90

ASTM Fb32 90 W 0759530 0057b73 b 9
r- aq -01
@$ Designation: F 632 - 90
AMERICAN SOCIETY FOR TESTINO AND MATERIALS
.-
1916 Racv SI., PhlladeQhk, Pa. 19103
Repfinled Ifom lhe Annuit Book d ASTM Slandirds Copriiohi ASTM
II n~l listed in the current comblned idx, WHI WU In ihr next dilion.
Standard Test Method for
Measuring Small-Signal Common Emitter Current Gain of
Transistors at High Frequencies'
This standard is issued under the fixed designation F 632; the number immediafely following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (6) indicates an editorial change since the last revision or reapproval.
- kThF.E
1. Scope
qzE
1.1 This test method covers the measurement of small-
where hFE is the di: current gain, IE is the d-c emitter current, in
signai, common-emitter current gain (h,J of transistors at
milliamperes, k is the Boltzmann constant, T is the absolute
high frequencies.
temperature, in kelvins, and q is the electronic charge.
NOTE 1-Parameters designated with upper-case subscripts refer to
di: operating conditions. Parameters designated with lower-case sub-
4. Summary of Test Method
scripts refer to small-signal a-c parameters.
4.1 A small-signal base current at the specified frequency
1.2 The test method is suitable for measurement of
is driven into the base of a transistor and adjusted to achieve
small-signal, common-emitter current gain at a single given
the desired collector current. The small-signal, a-c base and
value of small-signal, collector current and for a given set of
collector currents are measured and the gain calculated.
d-c bias conditions.
4.2 The following quantities are not specified by the test
1.3 The test method is limited to frequencies less than or
be agreed upon between the parties to the
method and shall
equal to 100 MHz.
test:
1.4 The test method is limited to currents below 0.2 A and
4.2.1 The d-c emitter current, ZE, at which the measure-
steady-state power dissipation of 50.5 PA, where PA is the
ment is to be made (see 7.9),
rated ambient power dissipation of the transistor under test.
4.2.2 The a-c collector current, i, at which the measure-
1.5 This standard may involve hazardous materials, oper-
ment is to be made, with the stipulation that, in order to
ations, and equipment. This standard does. not purport to
maintain small-signal conditions, the rms value of the small-
address all of the safety problems associated with its use. Zt is
signal collector current shali be chosen such that i, 5 O. 1 ZE,
the responsibility of the user of this standard to establish
4.2.3 The collector-base voltage, V,,, to be used for the
appropriate safity and health practices and determine the
measurement, and
applicability of regulatory limitations prior to use.
4.2.4 The measurement frequency, f; Hi.
2. Referenced Documents
5. Significance and Use
2.1 ASTM Standards:
5.1 Knowledge of hfi is required when using transistors in
E 178 Practice for Dealing with Outlying Observations'
high-frequency circuit applications.
E 69 1 Practice for Conducting an Interlaboratory Study to
5.2 Measurements of hIe can be used to determine the
Determine the Precision of a Test Method'
gain-bandwidth product, fT, an important parameter for
3. Terminology
high-frequency circuit applications.
5.3 The fest method is suitable in principle for specifica-
3.1 DeJinitions:
tion acceptance, service evaluation, or manufacturing con-
3.1.1 small-signal common-emitter current gain, hfi-of a
trol. Until an index of precision has been assigned, arising
transistor, the ratio of a-c collector current, i, to base
from an interlaboratory evaluation of the test method, the
current, ib, when the transistor is connected in the common-
emitter configuration. test method shall not be used for decisions between suppliers
and purchasen.
3.1.2 small-signal input impedance, hie-of a transistor,
the impedance from the base terminal to ground with the
collector terminal shorted to ground, when the transistor is 6. Interferences
connected in the common-emitter configuration.
6.1 Shunt Leakage-The magnitude of the impedance
NOTE 2-In this test method, the low-frequency value of hie is used
between the base and emitter connections on the test fature
to estimate certain component values (7.1.2, 7.1.3), and can be
must be much greater than the base-to-emitter impedance of
approximated by the expression
the transistor being tested. Otherwise, ' the measurement
results are invalid.
6.2 Inadequate Test Fixture-The test fature must be
'This test method is under the jurisdiction of ASTM Committee F-í on
carefully designed to meet the required d-c and a-c condi-
is the direct responsibilityof SubcommitteeFOí.11 on Quality and
Electronics and
tions, to avoid situafions that otherwise may make th
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