JP2010216921A - Test device and calibration method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a test device and calibration method, capable of reducing measurement time of the test device. <P>SOLUTION: The test device for a semiconductor device includes: a plurality of input/output circuits including a driver and a comparator; a calibration part measuring resistance of a transmission path; and a board for measurement provided with connection wiring electrically connecting input/output ends of the three or more input/output circuits. The calibration part outputs a voltage for measurement of a prescribed value to the connection wiring via the input/output end of the second input/output circuit when measuring the resistance of the transmission path corresponding to the first input/output circuit, measures the voltage of the connection wiring by using the comparator of the first input/output circuit, and measures the resistance of the transmission path on the basis of internal resistance of the driver of the first input/output circuit, the voltage measured by the comparator of the first input/output circuit, termination voltage, and the voltage for measurement. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a test apparatus and a calibration method.

  The semiconductor test apparatus outputs a test signal to the device under test and measures an output voltage of a response signal output from the device under test by a comparator. A semiconductor test apparatus may include a relay for switching signal connection between a comparator and a device under test (see, for example, Patent Document 1).

JP 2001-074816 A

  The relay has an on-resistance. Therefore, an error occurs in the measured value of the output voltage of the device under test due to the influence of the voltage drop due to the on-resistance or the like. Therefore, the semiconductor test apparatus needs to correct an error in measuring the output voltage of the device under test.

  As a method for correcting an error in a measured value, a method using an external power source connected to a semiconductor test apparatus is known. By applying a voltage from the outside to the input / output terminal of the semiconductor test apparatus, a correction value for the measurement error can be calculated based on the applied voltage and the voltage detected by the comparator. However, to calculate the correction value, it is necessary to disconnect the device under test from the semiconductor test apparatus and then connect an external power source. Moreover, it is necessary to connect an external power supply to the plurality of pins of the semiconductor test apparatus in order. Therefore, there is a problem that the measurement time of the device under test becomes long.

  In order to solve the above problems, in the first aspect of the present invention, a driver for outputting a predetermined voltage to an input / output line connected to the input / output terminal and a comparator for measuring the voltage of the input / output line are provided. Three or more input / output circuits, a mother board provided with a transmission path for electrically connecting the corresponding input / output circuits and the pins of the device under test, a calibration unit for measuring the resistance of the transmission path, When measuring resistance, a measurement board that is connected to the motherboard instead of the device under test and provided with connection wirings that electrically connect the input / output terminals of three or more input / output circuits to each other via the motherboard The calibration unit measures a resistance of the transmission line corresponding to the first input / output circuit, and sets a predetermined value to the connection wiring via the input / output terminal of the second input / output circuit. Output a constant voltage, detect the voltage of the connection wiring through the input / output terminal of the third input / output circuit, adjust the voltage output from the second input / output circuit based on the detected voltage, The output of the driver of the first input / output circuit is terminated with a predetermined termination voltage, the voltage of the connection wiring is measured using the comparator of the first input / output circuit, and the internal resistance of the driver of the first input / output circuit is measured. A test apparatus for measuring resistance of a transmission line based on a voltage measured by a comparator of a first input / output circuit, a termination voltage, and a measurement voltage, and a calibration method using the test apparatus are provided.

  In the second aspect of the present invention, an input / output circuit having a driver for outputting a predetermined voltage to an input / output line connected to the input / output terminal, a comparator for measuring the voltage of the input / output line, and the input / output circuit And a motherboard provided with a transmission path for electrically connecting the pins of the device under test, a calibration unit for measuring the resistance of the transmission path, and a mother board instead of the device under test when measuring the resistance of the transmission path And a measurement board provided with a ground wiring for grounding the input / output end of the input / output circuit via the motherboard, the calibration unit terminates the output of the driver with a predetermined termination voltage, Measure the voltage of the input and output lines, and measure the resistance of the transmission line based on the internal resistance of the driver, the voltage measured by the comparator, and the termination voltage That the test apparatus, as well as to provide a calibration method of using the test device.

  It should be noted that the above summary of the invention does not enumerate all the necessary features of the present invention. In addition, a sub-combination of these feature groups can also be an invention.

1 shows a configuration of a test apparatus 100 according to the present embodiment. 2 shows an equivalent circuit of a transmission line in the test apparatus 100. 1 shows a configuration of a test apparatus 100 when measuring resistance on a transmission line with respect to a first input / output circuit 20. The structure of the test apparatus 100 which concerns on other embodiment is shown. The structure of the test apparatus 100 which concerns on other embodiment is shown. 6 shows an equivalent circuit of a transmission line in the test apparatus 100 according to the embodiment shown in FIG.

  Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.

  FIG. 1 shows a configuration of a test apparatus 100 according to the present embodiment. The test apparatus 100 includes a first input / output circuit 20, a second input / output circuit 30, a third input / output circuit 40, a calibration unit 50, a motherboard 70, a socket board 80, and a test control unit 90. The device under test 200 is placed on the socket board 80. The device under test 200 has a pin 220, a pin 230, and a pin 240.

  The first input / output circuit 20 includes a driver 22 that outputs a predetermined voltage to the input / output line 21 connected to the input / output terminal 28, and a comparator 24 that measures the voltage of the input / output line 21. The second input / output circuit 30 includes a driver 32 that outputs a predetermined voltage to the input / output line 31 connected to the input / output terminal 38, and a comparator 34 that measures the voltage of the input / output line 31. The third input / output circuit 40 includes a driver 42 that outputs a predetermined voltage to the input / output line 41 connected to the input / output terminal 48, and a comparator 44 that measures the voltage of the input / output line 41. The test apparatus 100 may include three or more input / output circuits.

  The input / output line of each input / output circuit may be provided with a pin output relay that switches whether the driver and the comparator are electrically connected to the input / output terminal. For example, a pin output relay 26 may be provided on the input / output line 21 of the input / output circuit 20 between the driver 22 and the comparator 24 and the input / output terminal 28. Similarly, a pin output relay 36 may be provided in the input / output line 31. A pin output relay 46 may be provided on the input / output line 41.

  The motherboard 70 has a transmission path that electrically connects the corresponding input / output circuits and the pins of the device under test 200. For example, the mother board 70 includes a first input / output circuit 20 corresponding to the pin 220 of the device under test 200 and a transmission path 71 that connects the pin 220. Similarly, the motherboard 70 has a transmission path 73 and a transmission path 75 corresponding to the second input / output circuit 30 and the third input / output circuit 40. In each of the transmission path 71, the transmission path 73, and the transmission path 75, a connection relay 72, a connection relay 74, and a switching relay for switching whether or not the corresponding input / output circuit and the pin of the device under test are electrically connected, and A connection relay 76 is provided.

  When testing the device under test 200, the calibration unit 50 may perform a voltage application current measurement test in which a constant voltage is applied to a predetermined pin of the device under test 200 and current flowing through the pin is measured. The calibration unit 50 includes a measurement circuit 52, a voltage application relay 56, a voltage application relay 60, a voltage application relay 64, a voltage detection relay 58, a voltage detection relay 62, and a voltage detection relay 66. The calibration unit 50 selects one of the input / output circuits using the voltage application relay 56, the voltage application relay 60, the voltage application relay 64, the voltage detection relay 58, the voltage detection relay 62, and the voltage detection relay 66. The measurement circuit 52 applies a constant voltage to a predetermined pin of the device under test 200 via the selected input / output circuit, and measures the current supplied from the measurement circuit 52 to the pin. The measurement circuit 52 preferably has a high input impedance in order to detect the voltage with high accuracy.

  The test control unit 90 controls the test of the device under test 200. For example, the test control unit 90 may perform a voltage application current measurement test of the device under test 200. In this case, the test control unit 90 applies a predetermined test voltage to the device under test 200 from the input / output end of the predetermined input / output circuit using the measurement circuit 52. The measurement circuit 52 has a voltage output terminal 53 and a voltage detection terminal 54. The test control unit 90 adjusts the output voltage from the voltage output terminal 53 in accordance with the voltage at the input / output terminal of the input / output circuit detected by the voltage detection terminal 54, so that a constant voltage is applied to the device under test 200. You may test by applying. At this time, the quality of the device under test 200 may be determined based on whether or not the current value supplied from the measurement circuit 52 to the device under test 200 is within a predetermined range.

  For example, when applying a test voltage to the pin 220 of the device under test 200, the test control unit 90 controls the calibration unit 50 to turn on the voltage application relay 56 and the voltage detection relay 58 (relay terminals). (The state in which the gap is conducting). The test control unit 90 can apply a predetermined voltage to the pin 220 of the device under test 200 by adjusting the output voltage based on the voltage at the input / output terminal 28 detected via the voltage detection relay 58. .

  The test control unit 90 outputs a test signal having a predetermined pattern to the device under test 200 via the input / output circuit corresponding to each pin of the device under test 200, the motherboard 70, and the socket board 80. Thus, a function test of the device under test 200 may be performed. In this case, the voltage application relay and the voltage detection relay corresponding to the input / output circuit that outputs the test signal are in an off state (a state in which the relay terminals are not conductive). The test signal may be a signal having a predetermined logic pattern, a clock signal, or the like.

  In this case, the test control unit 90 outputs the device under test 200 according to the test signal via the comparators included in the socket board 80, the motherboard 70, and the input / output circuit corresponding to the pins of the device under test 200. A response signal is received. The test control unit 90 may determine whether the device under test 200 is good or bad by comparing the expected value corresponding to the output test signal with the received response signal.

  The voltage of the response signal output from the device under test 200 drops due to the resistance on the transmission path from the pin of the device under test 200 to the comparator. The resistance on the transmission path includes resistance components such as relays, wirings, and connectors. The test control unit 90 can measure the voltage value of the response signal with high accuracy by correcting the voltage value output from the comparator based on the resistance value of the resistance on the transmission path.

  FIG. 2 shows an equivalent circuit of a transmission path in the test apparatus 100. In the figure, the resistance on the transmission path is r, the output resistance of the driver 22 is R, the voltage applied to the driver 22 is VTT, the output voltage at the pin 220 of the device under test 200 is VS, and the measured voltage at the comparator 24 is V. It is said. The voltage value dropping in the transmission path is expressed by V−VS = r / (R + r) × (VTT−V). Therefore, the test apparatus 100 can calculate the drop voltage value in the transmission path by obtaining the correction value r / (R + r). When the output resistance R of the driver 22 is known, the test apparatus 100 may calculate a drop voltage value in the transmission path by obtaining the resistance r on the transmission path.

  FIG. 3 shows the configuration of the test apparatus 100 when measuring the resistance on the transmission path for the first input / output circuit 20. Instead of the socket board 80 in FIG. 1, a measurement board 82 is connected to the test apparatus 100 according to the present embodiment. The measurement board 82 may have the same shape as the socket board 80.

  The measurement board 82 is connected to the motherboard 70 instead of the socket board 80 and the device under test 200 when measuring the resistance of the transmission path. The measurement board 82 includes connection wirings 84 that electrically connect the input / output terminals of three or more input / output circuits to each other via the motherboard 70. Specifically, the measurement board 82 is connected to the mother board 70, and the input / output end 28, the input / output end 38, and the input / output end 48 are connected via the transmission path 71, the transmission path 73, and the transmission path 75. Are connected to each other.

  The measurement board 82 may include the function of the socket board 80. For example, the measurement board 82 may switch between a path used for testing the device under test 200 and a correction value measurement path using a switch or the like.

  Hereinafter, an operation in which the test apparatus 100 measures the resistance r of the transmission line 71 corresponding to the first input / output circuit 20 will be described. When measuring the resistance of the transmission line 71, the calibration unit 50 uses the voltage application relay 60 and the voltage detection relay 66. Therefore, in the present embodiment, a description will be given using a configuration in which the calibration unit 50 includes one voltage application relay and one voltage detection relay.

  The test apparatus 100 measures the resistance of the transmission path 71, the transmission path 73, and the transmission path 75 using the calibration unit 50. The calibration unit 50 may measure the on-resistance of the connection relay 72, the connection relay 74, and the connection relay 76.

  When the calibration unit 50 measures the resistance of the transmission line 71 corresponding to the first input / output circuit 20, the calibration unit 50 applies a predetermined value to the connection wiring 84 via the input / output terminal 38 of the second input / output circuit 30. Output measurement voltage. The calibration unit 50 detects the voltage of the connection wiring 84 via the input / output terminal 48 of the third input / output circuit 40. The calibration unit 50 adjusts the voltage output from the second input / output circuit 30 based on the detected voltage.

  Specifically, the calibration unit 50 is connected to the input / output terminal 48 of the third input / output circuit 40. The calibration unit 50 may be connected between the input / output terminal 48 of the third input / output circuit 40 and the pin output relay 46.

  The calibration unit 50 detects the voltage of the connection wiring 84 using the measurement circuit 52 having a higher input impedance than the comparator 24. For example, the measurement circuit 52 may output a measurement voltage from the voltage output terminal 53 and may detect the voltage at the voltage detection terminal 54. The calibration unit 50 terminates the output of the driver 22 included in the first input / output circuit 20 with a predetermined termination voltage and uses the comparator 24 included in the first input / output circuit 20 to connect the connection wiring 84. The voltage may be measured.

  Since the measurement circuit 52 has an input impedance higher than that of the driver 22, no current flows into the third input / output circuit 40. Therefore, no voltage drop occurs between the connection wiring 84 and the voltage detection end 54, and the calibration unit 50 can measure the voltage at the connection wiring 84 with high accuracy.

  Note that the calibration unit 50 may terminate the output of the driver 22 with a predetermined termination voltage via the test control unit 90. Further, the calibration unit 50 may terminate the output of the driver 22 with a predetermined termination voltage by applying a predetermined voltage to the driver 22.

  The calibration unit 50 includes an internal resistance R of the driver 22 included in the first input / output circuit 20, a voltage V measured by the comparator 24 of the first input / output circuit 20, a termination voltage VTT of the driver 22, and a measurement voltage. Based on VS, the resistance r of the transmission line 71 is measured. The calibration unit 50 may calculate the resistance r after obtaining the correction value r / (R + r).

  The voltage V measured by the comparator 24 is obtained by dividing the potential difference between the termination voltage VTT output from the driver 22 and the measurement voltage VS output from the measurement circuit 52 by the output resistance R of the driver 22 and the resistance r of the transmission path 71. Equal to voltage. That is, the voltage V measured by the comparator 24 is equal to V = r / (R + r) × (VTT−VS) + VS. Therefore, the calibration unit 50 can calculate the correction value r / (R + r) by r / (R + r) = (V−VS) / (VTT−VS). The calibration unit 50 can calculate the resistance value r of the transmission line 71 by measuring the output resistance R in advance.

  The calibration unit 50 may calculate the correction value by acquiring the values of VTT and V from the test control unit 90. Further, the test apparatus 100 may calculate a correction value in the test control unit 90.

  The calibration unit 50 may measure the combined resistance of the ON resistance of each connection relay and the ON resistance of each pin output relay. For example, the calibration unit 50 may measure the combined resistance of the on-resistance of the connection relay 72 and the pin output relay 26. Assuming that the combined resistance value of the connection relay 72 and the pin output relay 26 is r0, the calibration unit 50 sets the correction value r0 / (R + r0) to r0 / ( R + r0) = (V−VS) / (VTT−VS). As a result, the calibration unit 50 can calculate the combined resistance value r0.

  As described above, according to the test apparatus 100 according to the present embodiment, the resistance value of the transmission path can be calculated without connecting a device such as a power source outside the test apparatus 100. Therefore, the time required for measuring the resistance value of the transmission path in the test apparatus 100 can be shortened.

  FIG. 4 shows a configuration of a test apparatus 100 according to another embodiment. In the figure, the calibration unit 50 has a voltage application relay and a voltage detection relay corresponding to each input / output circuit. The voltage output terminal 53 of the measurement circuit 52 is connected between the pin output relay and the input / output terminal of each input / output circuit via a voltage application relay. The voltage detection terminal of the measurement circuit is connected between the pin output relay and the input / output terminal of each input / output circuit via a voltage detection relay.

  Specifically, the voltage output terminal 53 is connected between the pin output relay 26 and the input / output terminal 28 via a voltage application relay 56. The voltage output terminal 53 is connected between the pin output relay 36 and the input / output terminal 38 via a voltage application relay 60. Further, the voltage output terminal 53 is connected between the pin output relay 46 and the input / output terminal 48 via a voltage application relay 64.

  On the other hand, the voltage detection end 54 is connected between the pin output relay 26 and the input / output end 28 via a voltage detection relay 58. The voltage detection terminal 54 is connected between the pin output relay 36 and the input / output terminal 38 via the voltage detection relay 62. Further, the voltage detection terminal 54 is connected between the pin output relay 46 and the input / output terminal 48 via a voltage detection relay 66.

  The voltage application relay 56 and the voltage detection relay 58 may be connected to each other at terminals different from the respective terminals connected to the measurement circuit 52. Similarly, the voltage application relay 60 and the voltage detection relay 62 and the voltage application relay 64 and the voltage detection relay 66 may be connected to each other at a terminal different from the terminal connected to the measurement circuit 52.

  When measuring the combined resistance of the connection relay and the pin output relay corresponding to each input / output circuit, the calibration unit 50 determines the voltage application relay, voltage detection according to the input / output circuit including the combined resistance to be measured. Switches the status of relays, pin output relays, and connection relays. For example, when measuring the combined resistance of the connection relay 72 and the pin output relay 26 corresponding to the first input / output circuit 20, the calibration unit 50 switches the state of each relay as follows.

  The calibration unit 50 turns off the voltage application relay 56 and the voltage detection relay 58 in the first input / output circuit 20 (a state in which the relay terminals are not conductive) and turns on the pin output relay 26. To do. Further, the calibration unit 50 turns off the voltage detection relay 62 and the pin output relay 36 in the second input / output circuit 30 and turns on the voltage application relay 60. Similarly, the calibration unit 50 turns off the voltage application relay 64 and the pin output relay 46 in the third input / output circuit 40 and turns on the voltage detection relay 66. Further, the calibration unit 50 turns on each connection relay in the motherboard 70.

  In this state, the current output from the voltage output terminal 53 flows into the driver 22 via the voltage application relay 60, the connection relay 74, the connection wiring 84, the connection relay 72, and the pin output relay 26. The test control unit 90 acquires the voltage V of the input / output line 21 detected by the comparator 24. The test control unit 90 notifies the calibration unit 50 of the acquired voltage V of the input / output line 21 and the voltage VTT output by the driver 22.

  The measurement circuit 52 measures the voltage value VS applied to the connection wiring 84 by measuring the voltage applied to the voltage detection end 54. The calibration unit 50 calculates a correction value based on the voltage V and the voltage VTT acquired from the test control unit 90 and the voltage VS detected by the measurement circuit 52. The calibration unit 50 may calculate the combined resistance of the connection relay 72 and the pin output relay 26 based on the calculated correction value and the output resistance R of the driver 22.

  The calibration unit 50 can also measure the on-resistance of the pin output relay by controlling the voltage application relay, the voltage detection relay, the pin output relay, and the connection relay. Specifically, the calibration unit 50 turns on the voltage application relay 56, the voltage detection relay 58, and the pin output relay 26 in the first input / output circuit 20. At the same time, the calibration unit 50 turns off other voltage application relays, voltage detection relays, pin output relays, and connection relays.

  Further, the calibration unit 50 applies a predetermined measurement voltage VS from the measurement circuit 52 to the first input / output circuit 20. The calibration unit 50 can measure the on-resistance of the pin output relay 26 by measuring the voltage V applied to the comparator 24 in the first input / output circuit 20.

  Specifically, the measurement voltage VS is applied to the terminal on the input / output end 28 side of the pin output relay 26. Therefore, if the on-resistance value of the pin output relay 26 is r1, as in the previous example, the correction value r1 / (R + r1) is given by r1 / (R + r1) = (V−VS) / (VTT−VS). Desired. As a result, the calibration unit 50 can calculate the on-resistance value r1 of the pin output relay 26 based on the calculated correction value and the output resistance R of the driver 22.

  The calibration unit 50 can also calculate the on-resistance value r2 of the connection relay. Specifically, the calibration unit 50 may calculate the on-resistance value r2 of the connection relay based on the measured combined resistance value r0 and the on-resistance value of the pin output relay r1. For example, the calibration unit 50 measures the on-resistance value r1 of the pin output relay 26 after measuring the combined resistance value r0 of the pin output relay 26 and the connection relay 72. The calibration unit 50 can calculate the on-resistance value r2 of the connection relay 72 by r2 = r0−r1 by subtracting the on-resistance value r1 of the pin output relay 26 from the measured combined resistance value r0.

  Furthermore, the calibration unit 50 can cause the measurement circuit 52 to output measurement voltages having a plurality of types of voltage values and measure the resistance of the transmission path with respect to each measurement voltage. Thereby, even if it is a case where ON resistance of each relay is fluctuate | varied according to an applied voltage, the calibration part 50 can measure the resistance of a transmission line according to an applied voltage. The calibration unit 50 may include a memory that stores each measurement voltage and the resistance of the transmission path in association with each other.

  In the above description, the operation of calculating the resistance value of the transmission line 71 corresponding to the first input / output circuit 20, the ON resistance value of the pin output relay 26, and the ON resistance value of the connection relay 72 has been described. The calibration unit 50 is configured to turn on the voltage application relay, the voltage detection relay, the pin output relay, and the connection relay in other different combinations to thereby turn on the second input / output circuit 30 and the third input / output circuit. For 40, the resistance of the transmission path can also be measured.

  The calibration unit 50 may be connected to more input / output circuits. For example, the measurement circuit 52 may be connected to 16 input / output circuits. In this case, the calibration unit 50 first turns on the voltage application relay 56 corresponding to the first input / output circuit 20 and the voltage detection relay 62 corresponding to the second input / output circuit 30. Then, the resistance of the transmission path corresponding to a predetermined number of input / output circuits other than the first input / output circuit 20 and the second input / output circuit 30 is measured.

  Subsequently, the calibration unit 50 includes a voltage application relay corresponding to any one of the input / output circuits other than the first input / output circuit 20 and the second input / output circuit 30 and any other input / output circuit. Turn on the corresponding voltage detection relay. In this state, the calibration unit 50 may measure the resistance of the transmission path corresponding to the unmeasured input / output circuit including the first input / output circuit 20 and the second input / output circuit 30. The calibration unit 50 can measure the resistance of the transmission path for all the input / output circuits by performing measurement at least twice.

  In addition, the calibration unit 50 divides the input / output circuits connected to approximately half of the input / output circuits, and applies voltage input relays corresponding to different input / output circuits for each input / output circuit group. The resistance of the transmission path may be measured by turning on the voltage detection relay. By controlling in this way, the maximum current output from the measurement circuit 52 becomes substantially equal in each input / output circuit group. Therefore, the current capacity required by the measurement circuit 52 is minimized. As a result, the measurement circuit 52 can be reduced in size and cost.

  Further, the calibration unit 50 may determine the number of input / output circuit groups that simultaneously measure the on-resistance based on the maximum output current value of the measurement circuit 52 and the maximum consumption current value of the input / output circuit. For example, when the maximum output current value of the measurement circuit 52 is 2 (A) and the maximum current consumption value of each input / output circuit is 300 (mA), the calibration unit 50 has six input currents. The output circuit may be measured simultaneously. The calibration unit 50 determines the number of input / output circuit groups to be simultaneously measured based on the maximum output current value of the measurement circuit 52 and the maximum current consumption value of the input / output circuit, thereby enabling simultaneous measurement of input / output circuit groups. The number of can be optimized.

  FIG. 5 shows a configuration of a test apparatus 100 according to another embodiment. In the figure, the test apparatus 100 includes a first input / output circuit 20, a mother board 70, a measurement board 86, and a calibration unit 50. The first input / output circuit 20 includes a driver 22 that outputs a predetermined voltage to the input / output line 21 connected to the input / output terminal 28, and a comparator 24 that measures the voltage of the input / output line 21. The motherboard 70 has a transmission line 71 that electrically connects the pins of the input / output circuit 20 and the device under test 200. The first input / output circuit 20 may include a pin output relay 26 between the driver 22 and the input / output terminal 28.

  The measurement board 86 is connected to the motherboard 70 in place of the device under test 200 when measuring the resistance value of the transmission line 71. The measurement board 86 has a ground wiring 88 for grounding the input / output terminal 28 of the input / output circuit 20 via the mother board 70.

  The calibration unit 50 measures the resistance value of the transmission path 71. After the output of the driver 22 is terminated with a predetermined termination voltage VTT, the voltage V of the input / output line 21 is measured using the comparator 24. The calibration unit 50 may measure the resistance of the transmission line 71 based on the internal resistance R of the driver 22, the voltage V measured by the comparator 24, and the termination voltage VTT.

  FIG. 6 shows an equivalent circuit of the test apparatus 100 according to the embodiment shown in FIG. The combined resistance of the input / output line 21 and the transmission line 71 is r, and the voltage detected by the comparator 24 is V. The combined resistance r includes ON resistances of the pin output relay 26 and the connection relay 72. In this case, the voltage measured by the comparator 24 is a voltage obtained by dividing the termination voltage VTT of the driver 22 by the output resistor R and the combined resistor r of the driver 22. Therefore, the voltage measured by the comparator 24 is expressed as V = r / (R + r) × VTT.

  Thus, the calibration unit 50 can calculate the correction value r / (R + r) as r / (R + r) = V / VTT. The calibration unit 50 can obtain the combined resistance value r based on the calculated correction value and the output resistance R of the driver 22.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  The order of execution of each process such as operations, procedures, steps, and stages in the apparatus, system, program, and method shown in the claims, the description, and the drawings is particularly “before” or “prior to”. It should be noted that the output can be realized in any order unless the output of the previous process is used in the subsequent process. Regarding the operation flow in the claims, the description, and the drawings, even if it is described using “first”, “next”, etc. for convenience, it means that it is essential to carry out in this order. It is not a thing.

  20 Input / Output Circuit, 21 Input / Output Line, 22 Driver, 24 Comparator, 26 Pin Output Relay, 28 Input / Output Terminal, 30 Input / Output Circuit, 31 Input / Output Line, 32 Driver, 34 Comparator, 36 Pin Output Relay, 38 Input / Output Terminal, 40 input / output circuit, 41 input / output line, 42 driver, 44 comparator, 46 pin output relay, 48 input / output terminal, 50 calibration section, 52 measurement circuit, 53 voltage output terminal, 54 voltage detection terminal, 56 voltage application Relay, 58 Voltage detection relay, 60 Voltage application relay, 62 Voltage detection relay, 64 Voltage application relay, 66 Voltage detection relay, 70 Motherboard, 71 Transmission path, 72 Connection relay, 73 Transmission path, 74 Connection relay, 75 Transmission path, 76 connection relay, 80 socket board, 82 measurements Board, 84 connection wiring, 86 measuring board 88 ground wiring, 90 test control unit, 100 the test apparatus, 200 a device under test, 220-pin, 230-pin, 240-pin

Claims (13)

A test apparatus for testing a device under test,
A driver for outputting a predetermined voltage to an input / output line connected to the input / output terminal, and three or more input / output circuits each having a comparator for measuring the voltage of the input / output line;
A motherboard provided with a transmission path for electrically connecting the corresponding input / output circuit and the pin of the device under test;
A calibration unit for measuring the resistance of the transmission path;
When measuring the resistance of the transmission line, a connection wiring that is connected to the motherboard instead of the device under test and electrically connects the input / output terminals of three or more input / output circuits to each other via the motherboard And a measurement board provided with
The calibration unit measures the resistance of the transmission path corresponding to the first input / output circuit,
A measurement voltage having a predetermined value is output to the connection wiring via the input / output terminal of the second input / output circuit;
Detecting the voltage of the connection wiring through the input / output terminal of the third input / output circuit, and adjusting the voltage output from the second input / output circuit based on the detected voltage;
Terminate the output of the driver of the first input / output circuit with a predetermined termination voltage, and measure the voltage of the connection wiring using the comparator of the first input / output circuit;
The resistance of the transmission line is measured based on the internal resistance of the driver of the first input / output circuit, the voltage measured by the comparator of the first input / output circuit, the termination voltage, and the measurement voltage. To test equipment. The test according to claim 1, wherein the calibration unit is connected to the input / output terminal of the third input / output circuit and detects a voltage of the connection wiring using a measurement circuit having an input impedance higher than that of the comparator. apparatus. Each transmission path of the motherboard is provided with a connection relay that switches whether to electrically connect the corresponding input / output circuit and the pin of the device under test,
The test apparatus according to claim 2, wherein the calibration unit measures an on-resistance of the connection relay. The input / output line of each of the input / output circuits is provided with a pin output relay for switching whether to electrically connect the driver and the comparator and the input / output terminal,
The test apparatus according to claim 3, wherein the calibration unit measures a combined resistance of an on-resistance of the connection relay and an on-resistance of the pin output relay. The voltage output terminal of the measurement circuit is connected between the pin output relay and the input / output terminal of each input / output circuit via a voltage application relay,
The test apparatus according to claim 4, wherein the voltage detection terminal of the measurement circuit is connected between the pin output relay and the input / output terminal of each of the input / output circuits via a voltage detection relay. When the calibration unit measures a combined resistance of the connection relay and the pin output relay corresponding to the first input / output circuit,
The voltage application relay and the voltage detection relay in the first input / output circuit are turned off, the pin output relay is turned on,
The voltage detection relay and the pin output relay in the second input / output circuit are turned off, the voltage application relay is turned on,
The voltage application relay and the pin output relay in the third input / output circuit are turned off, the voltage detection relay is turned on,
The test apparatus according to claim 5, wherein each connection relay in the motherboard is turned on. The calibration unit turns on the voltage application relay, the voltage detection relay, and the pin output relay in the first input / output circuit, applies a predetermined measurement voltage from the measurement circuit, and The test apparatus according to claim 6, further measuring an on-resistance of the pin output relay in the first input / output circuit by measuring a voltage applied to the comparator in the first input / output circuit. The test apparatus according to claim 7, wherein the calibration unit calculates an on-resistance of the connection relay based on the measured combined resistance and an on-resistance of the pin output relay. The said calibration part makes the said measurement circuit output the said voltage for a measurement of several types of voltage values, and measures the resistance of the said transmission line with respect to each said voltage for a measurement. The test apparatus described in 1. Using the measurement circuit, a predetermined test voltage is applied to the device under test from the input / output end of the predetermined input / output circuit, and the measurement circuit The test apparatus according to claim 2, further comprising a test control unit that performs a test by applying a constant voltage to the device under test by adjusting an output voltage. A calibration method for calibrating a test apparatus for testing a device under test,
The test apparatus comprises:
A driver for outputting a predetermined voltage to an input / output line connected to the input / output terminal, and three or more input / output circuits each having a comparator for measuring the voltage of the input / output line;
A motherboard provided with a transmission path for electrically connecting the corresponding input / output circuit and the pin of the device under test;
A calibration unit for measuring the resistance of the transmission path;
When measuring the resistance of the transmission line, a connection wiring that is connected to the motherboard instead of the device under test and electrically connects the input / output terminals of three or more input / output circuits to each other via the motherboard And a measurement board provided with
When measuring the resistance of the transmission line corresponding to the first input / output circuit,
A measurement voltage of a predetermined value is output to the connection wiring via the input / output terminal of the second input / output circuit;
Detecting the voltage of the connection wiring through the input / output terminal of the third input / output circuit, and adjusting the voltage output from the second input / output circuit based on the detected voltage;
Terminate the output of the driver of the first input / output circuit with a predetermined termination voltage, and measure the voltage of the connection wiring using the comparator of the first input / output circuit;
A calibration method for measuring the resistance of the transmission line based on the internal resistance of the driver of the first input / output circuit, the voltage measured by the comparator of the first input / output circuit, and the measurement voltage . A test apparatus for testing a device under test,
A driver for outputting a predetermined voltage to an input / output line connected to the input / output terminal; and an input / output circuit having a comparator for measuring the voltage of the input / output line;
A motherboard provided with a transmission path for electrically connecting the input / output circuit and the pins of the device under test;
A calibration unit for measuring the resistance of the transmission path;
When measuring the resistance of the transmission line, a measurement board provided with a ground wiring connected to the motherboard instead of the device under test and grounding the input / output end of the input / output circuit via the motherboard And
The calibration unit terminates the output of the driver with a predetermined termination voltage, measures the voltage of the input / output line using the comparator,
A test apparatus that measures the resistance of the transmission line based on the internal resistance of the driver, the voltage measured by the comparator, and the termination voltage. A calibration method for calibrating a test apparatus for testing a device under test,
The test apparatus comprises:
A driver for outputting a predetermined voltage to an input / output line connected to the input / output terminal; and an input / output circuit having a comparator for measuring the voltage of the input / output line;
A motherboard provided with a transmission path for electrically connecting the input / output circuit and the pins of the device under test;
A calibration unit for measuring the resistance of the transmission path;
When measuring the resistance of the transmission line, a measurement board provided with a ground wiring connected to the motherboard instead of the device under test and grounding the input / output end of the input / output circuit via the motherboard And
Terminate the output of the driver with a predetermined termination voltage, measure the voltage of the input / output line using the comparator,
A calibration method for measuring a resistance of the transmission line based on an internal resistance of the driver, a voltage measured by the comparator, and the termination voltage.

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