Waveform input circuit, waveform observation unit and semiconductor test apparatus

• US 20070268012A1
• Filed: 03/03/2006
• Published: 11/22/2007
• Est. Priority Date: 03/04/2005
• Status: Active Grant

• Current Assignee: Advantest Corporation
• Original Assignee: Advantest Corporation
• Inventors: Kawabata, Masayuki
• Granted Patent: US 7,634,370 B2
• Time in Patent Office: Days
• US Class Current: 324/120
• CPC Class Codes: G01R 31/31924 Voltage or current aspects, e.g. driver, receiver
• CPC Class Codes: G01R 31/31926 Routing signals to or from the device under test [DUT], e.g. switch matrix, pin multiplexing

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”.

Claims

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”

.

2. The waveform input circuit according to claim 1, comprising:

a DC measurement interrupt path to be connected to perform a DC measurement,

wherein one reference potential which is switched by the switch means is “

a guard line of the DC measurement interrupt path”

.

3. The waveform input circuit according to claim 1, comprising:

a plurality of input signal transmission lines,

wherein the switch means switches the reference potentials of some of the input signal transmission lines to at least two kinds of different potentials.

4. The waveform input circuit according to any one of claims 1, comprising:

an envelope drive amplifier which provides a voltage to the envelope of the input signal transmission line, when the switch means switches one reference potential to “

the 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”

.

5. A waveform observation unit comprising:

a waveform input circuit to which an analog waveform output from a device under test is input;

an A/D converter which converts the analog waveform into digital data; and

a waveform acquisition memory which records the digital data,

wherein the waveform input circuit includes a waveform input circuit according to any one of claims 1 to 4.

6. A semiconductor test apparatus comprising a waveform observation unit to observe an analog waveform output from a device under test,

wherein the waveform observation unit includes a waveform observation unit according to claim 5.