Waveform input circuit, waveform observation unit and semiconductor test apparatus
First Claim
1. A waveform input circuit to which a signal from a device under test is input via an input signal transmission line, the waveform input circuit comprising:
- a high input impedance terminating resistance which receives the signal from the input signal transmission line as an input signal;
selection means for selecting one of two or more terminating resistances including the high input impedance terminating resistance;
an input buffer which is connected when the high input impedance terminating resistance is selected in the selection means; and
switch means for switching a reference potential of the input signal transmission line to at least two kinds of different potentials, wherein one reference potential which is switched by the switch means is “
a potential controlled to be in phase with the input signal by an output voltage of the input buffer which is connected when the high input impedance terminating resistance is selected in the selection means”
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1 Assignment
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Accused Products
Abstract
An output waveform of a device under test with high output impedance and low load driving capability is faithfully observed.
A waveform input circuit 10 comprises a high input impedance terminating resistance which receives an input signal from a transmission line 11, selection means (relay) 12 which selects any one of this terminating resistance and other terminating resistances, and an input buffer 13 which is connected when the high input impedance terminating resistance is selected in the selection means 12, wherein switch means 16 is provided to switch the reference potential of the transmission line 11 to at least two kinds of reference potentials, and one reference potential which is switched by the switch means 16 is “a potential controlled to be in phase with the input signal by an output voltage of the input buffer 13 which is connected when the high input impedance terminating resistance is selected in the selection means 12”.
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Citations
6 Claims
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1. A waveform input circuit to which a signal from a device under test is input via an input signal transmission line, the waveform input circuit comprising:
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a high input impedance terminating resistance which receives the signal from the input signal transmission line as an input signal;
selection means for selecting one of two or more terminating resistances including the high input impedance terminating resistance;
an input buffer which is connected when the high input impedance terminating resistance is selected in the selection means; and
switch means for switching a reference potential of the input signal transmission line to at least two kinds of different potentials, wherein one reference potential which is switched by the switch means is “
a potential controlled to be in phase with the input signal by an output voltage of the input buffer which is connected when the high input impedance terminating resistance is selected in the selection means”
. - View Dependent Claims (2, 3, 4, 5, 6)
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Specification