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HQ 084659

August 25, 1989

CLA-2 CO:R:C:G 084659 AJS


TARIFF NO: 8541.29.00; 8542.20.00

Mr. Donald Alford Weadon, Jr.
Weadon, Rehm, Thomsen & Scott
Suite 500
1301 Pennsylvania Avenue, N.W.
Washington, D.C. 20004

RE: Transistor modules from Japan

Dear Mr. Weadon:

Your letter of April 25, 1989, on behalf of Toshiba America Electronics Components 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 three types of transistor modules to be imported from Japan. The first is the Bipolar Darlington Transistor Module (BDTM). The BDTM is a multi- terminal device consisting of single or multiple transistor diode parts {directly mounted on a direct bond copper circuit board (DBCCB)} capable of amplification, oscillation, frequency, or switching of electrical currents, behaving essentially as a single transistor device with a high current and power rating. Variation in resistivity between two of the terminals results from the application of an electrical field or control signal to a third terminal, whose transistor action depends on both positive and negative charge carriers.

The second is the Metal Oxide Semiconductor Field Effect Transistor (MOS-FET). The MOS-FET is a unipolar, voltage- controlled device consisting of single or multiple transistor diode parts (directly mounted on a DBCCB) whose output depends on the induced depletion or enhancement of charge carriers between at least two terminals. Its output current can be controlled using very low gate drive power levels. It can be maintained in an "on" or "off" state with essentially no input gate power,
requiring only relatively small gate pulse currents to charge and discharge its input gate capacities during switching.

The third is the Insulated Gate Bipolar Transistor Module (IGBT) which combines both bipolar and power MOS-FET technologies, (likewise consisting of single or multiple transistor diode parts directly mounted on a DBCCB) rendering high input impedance as well as high forward conduction current density. Containing two back-to-back high voltage junctions, it is capable of symmetrical forward and reverse blocking capacity.


Whether the articles in question 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.


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.

Transistors include:

(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, bipolar).

(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."

The BDTM meets the Explanatory Notes description of tran- sistors. It is a multi-terminal device capable of amplification, oscillation, frequency conversion, or switching of electrical currents. Its operation also depends on the variation in resistivity between two of the terminals upon the application of an electric field to a third terminal.

The MOS-FET satisfies the Explanatory Note (II) (2) description of field effect transistors. It is a unipolar metal oxide semiconductor which depends on the induced depletion or enhancement of available charge between two terminals.

Lastly, the IGBT also satisfies the Explanatory Notes description of transistors. It combines both the bipolar technology of the BDTM as well as the power of the MOS-FET, but with allowance for greater adaptability. More specifically, it possesses both the high input impedance and high speed characteristics of the MOS-FET while it also contains the high conductivity characteristic of the BDTM transistor.

In sum, all three of the above transistor modules meet 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 8541.

You state that the trade practice of 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 both BDTM and MOS-FET transistors as discrete semiconductor devices. 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 semiconductor 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 semiconductor devices."

In addition, independent authority recommended to this office by the Semiconductor Association of San Jose, California, confirm that the transistor module is considered by the trade to be a transistor. The Darlington Transistor Module is reported
by the industry in their statistics as transistors. 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 can not 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.

The articles in question are also not hybrid integrated circuits because they are produced in a different manner than that which is described in note 5(B)(b) above. All three are mounted on a Direct Bond Copper Circuit Board which does not involve the thin/thick film technology traditionally used to produce hybrid integrated circuits.


The three transistor modules in question are properly classifiable as other transistors with a dissipation rate of more than 1 W, 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 1 W they would instead be classifiable in subheading 8541.21.00, free of duty.


John Durant, Director
Commercial Rulings Division

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