CLA-2 CO:R:C:G 084660 AJS
Mr. Joseph A. Black
Dewey, Ballantine, Bushby, Palmer & Wood
1775 Pennsylvania Avenue, N.W.
Washington, D.C. 20006
RE: Transistor modules from Japan
Dear Mr. Black:
Your letter of April 25, 1989, on behalf of Collmer
Semiconductor Inc., requesting a tariff classification under the
Harmonized Tariff Schedule of the United States Annotated
(HTSUSA) has been referred to this office for reply.
The articles in question are described as power transistors
and Darlington transistors. They are composed of a Darlington
Transistor Chip, which consists of two or more transistors and
resistors on the same semiconductor material. Technically,
Darlington transistors are a form of monolithic integrated
circuit. There are two of these chips in each device.
The Darlington transistors are also composed of diode chips.
There are two types of diodes in each transistor. One is a high
current diode connected from the collector to the emitter of each
Darlington chip. These diodes are referred to as fast recovery
diodes (FRD). The other type, a speed up diode (SUD), is
connected from the base to the emitter of the first two stages of
each Darlington chip. All diodes, six in total, are on separate
The individual chips described above are mounted on a thick-
film substrate. The thick-film substrate also serves to
electrically isolate the chips from the base plate of the device
assembly, a technology that is common to hybrid integrated
The top service elements of the Darlington transistor and
diode chips are interconnected by wire bonding to bus bars and
external terminals. The internal parts and circuits are sealed
with silicon rubber and epoxy resin. This assembly is enclosed
within a plastic cover.
Whether Darlington transistors are properly classifiable in
subheading 8541.29.00, HTSUSA, which provides for other
transistors; or in subheading 8542.20.00, HTSUSA, which provides
for hybrid integrated circuits.
LAW & ANALYSIS
Chapter 85, note 5 (a), HTSUSA, states transistors are semi-
conductor devices, "the operation of which depends on variations
in resistivity on the application of an electric field." The
Explanatory Notes, for heading 8541 at (A)(II) describe
transistors as follows:
"Transistors are three- or four- terminal devices capable of
amplification, oscillation, frequency conversion, or
switching of electrical currents. The operation of a
transistor depends on the variation in resistivity between
two of the terminals upon the application of an electric
field to the third terminal. The applied control signal or
field is weaker than the resulting action brought about by
the change in resistance and thus amplification results.
(1) Bipolar transistors, which are three terminal
devices consisting of two diode type junctions,
and whose transistor action depends on both
positive and negative charge carriers (hence,
(2) Field effect transistors (also known as metal oxide
semiconductors (MOS)), which may or may not have a
junction, but which depend on the induced depletion
(or enhancement) of available charge carriers
between two of the terminals. The transistor
action in a field effect transistor employs only
one type of charge carriers (hence, unipolar).
MOS type transistors which have four terminals are
known as tetrodes."
In ruling letter HQ 084659 this office held that similar
Darlington transistors met the Chapter and Explanatory Notes
description of transistors. This office found that Darlington
transistors are multi-terminal devices which are capable of
amplification, oscillation, frequency conversion, or switching of
electrical currents. The operation of the Darlington transistor
depends on the variation in resistivity between two of the
terminals upon the application of an electric field to a third
terminal. For the same reasons as listed above, the transistors
in question are a similar type of Darlington transistor which
also meets the HTSUSA's description of transistors.
In sum, Darlington transistors modules satisfy the
Explanatory Notes description of how transistors operate
electronically. Also, none of these provisions or any other
section or chapter notes specifically exclude transistor modules
operating in an identical manner as transistors from heading
Trade practice in the industry also supports the
classification of the articles in question as transistors. The
Joint Electronic Device Engineering Council (JEDEC), which is an
organization leading a comprehensive and industry wide effort to
harmonize all basic semiconductor definitions, classifies the
Darlington transistor as a discrete semiconductor device. The
JEDEC defines a discrete semiconductor device as a "device that
is specified to perform an elementary electronic function and
that is not divisible into separate components functional in
themselves." They list transistors as examples of discrete semi-
conductor devices, and state that "other semiconductor structures
having the physical complexity of integrated circuits but
performing elementary electronic functions (e.g., complex
Darlington transistors) are usually considered to be discrete
In addition, independent authority recommended to this
office by the Semiconductor Association of San Jose, California,
confirm that the Darlington transistor module is considered by
the trade to be a transistor. The Darlington transistor module
is reported by the industry in their statistics as a transistor.
They are also not considered to be integrated circuits by the
industry. Thus trade practice as well as the HTSUSA Chapter and
Explanatory Notes indicate that transistor modules are considered
transistors and not integrated circuits.
Subheading 8542.20.00, HTSUSA, provides for hybrid
integrated circuits. Chapter 85, Note 5(B)(b) states that hybrid
integrated circuits are electronic integrated circuits in which
passive elements, obtained by thin- or thick film technology, and
active elements (transistors etc.), obtained by semiconductor
technology, are combined to all intents and purposes indivisibly,
on a single insulating substrate (glass, ceramic, etc.). In
making a distinction between transistors and integrated circuits,
Explanatory Note 85.42 (II) describes transistors as discrete
components which are indivisible and possess a single active
electrical function. While in contrast, integrated circuits are
described as components consisting of several electric circuit
elements which have multiple electrical functions, and that are
not considered as discrete components. Therefore, the articles
in question cannot be considered as the hybrid integrated
circuits described above. They are instead discrete indivisible
components which can only perform a single function and not
multiple circuits that perform multiple functions.
In conclusion, Darlington transistor modules are
classifiable as transistors. This conclusion is based on both
the Chapter and Explanatory Notes as well as relevant trade
practice. These articles are not hybrid integrated circuits,
even though in some cases they are produced by thick film
technology, because they do not function in the same manner.
They are instead transistors, which are discrete indivisible
components that perform a single active electric function.
The Darlington transistors in question are properly
classifiable as other transistors with a dissipation rate of more
than 1W, provided for in subheading 8541.29.00, free of duty.
This conclusion regarding dissipation rate is based on the fact
that these articles are used in power circuits. However, if they
in fact do possess a dissipation rate of less than 1W they would
instead be classifiable in subheading 8541.21.00, free of duty.
John Durant, Director
Commercial Rulings Division