Appeal No. 1997-0179
Application 08/251,054
DRAM memory device (see Figures 4 and 5 of the specification) for providing on chip power supply
control by producing a burn-in reference voltage (V ) (see specification, page 1). As indicated in
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the specification (page 3), a burn-in operation is performed on each memory device during a test
process of the chips. As stated by appellant, "[b]urn-in is intended to stress the devices, both by
voltage and by temperature so that weak devices are removed from the population which is shipped to
the user of the devices" (specification, page 3).
In general, appellant’s invention recited in independent claims 1 and 5 on appeal provides a
memory device (Figures 4 and 5) having input (nodes 342 and 350), feedback (transistor 301), and
mirroring (transistors 306-318) circuits which work in concert together to better provide a burn-in
reference voltage (V ). More specifically, appellant’s claimed invention produces a burn-in voltage
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by mirroring a feedback voltage to produce a mirrored voltage having a magnitude approximately the
same as the feedback voltage, wherein the mirrored voltage is measured in relation of an external
reference voltage (V ) (see last paragraph of each of independent claims 1 and 5 on appeal). By
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providing the burn-in reference voltage with respect to an external reference voltage (V ), a burn-in
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reference voltage (V ) is provided which "is both stable with respect to temperature and process"
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(specification, page 7, Summary of the Invention). As further discussed, infra, we find that the applied
reference to Fischer fails to teach or suggest at least this salient feature as it is recited in the claims on
appeal.
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