Appeal No. 1997-4442
Application 08/353,040
The Examiner alternatively rejects claims 6 and 2 as
unpatentable for obviousness based on de Wit and the APA that
trimming was well known. The rejection, as we understand it,
is that it would have been obvious to trim the resistor
portions in de Wit to achieve a desired resistance and TCR in
view the APA description of trimming a precision resistor by
trimming a first path portion to a desired resistance and
trimming a second path portion to a desired TCR
(specification, page 1, line 25, to page 2, line 2). We
address only the rejection as stated, which does not rely on
the resistor construction in the admitted prior art of Chapel.
Appellants argue that the prior art trimming of the
adjustment portion will not work when the TCR of the resistor
is already greater than zero because it will simply increase
the positive TCR further away from zero (Br6). This argument
refers to the problem in Chapel and does not discuss why it
would have been unobvious to trim the resistor in de Wit to
achieve a desired resistance and TCR in view the APA. While
we might speculate that trimming would be difficult for the
semiconductor resistor construction in de Wit, in the absence
of argument by Appellants we will not conclude that the
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