JP2009216565A - Semiconductor integrated circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor integrated circuit for accurately measuring a resistance of a termination resistor, and reducing the number of input/output terminals. <P>SOLUTION: A control circuit of the semiconductor integrated circuit 100 turns on first and second switch circuits in a test operation mode for measuring the resistance of the termination resistor, and turns off the first and second switch circuits in a normal operation mode for implementing a normal operation. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a semiconductor integrated circuit capable of measuring a resistance value of an internal termination resistor.

  In recent years, an LVDS (Low Voltage Differential Signaling) interface circuit, which is a semiconductor integrated circuit using current as a signal transmission means, is used as one of means for transmitting a large amount of signals.

  In this LVDS circuit, a 100Ω termination resistor is connected immediately before the input of the receiver circuit. This termination resistor may be incorporated in a semiconductor integrated circuit in order to reduce the number of product parts. A specification determined as a product is defined for the resistance value of the termination resistor. As this specification, for example, a range of 100Ω ± 15Ω is determined.

  In order to guarantee the resistance value with the product, it is necessary to measure the resistance value on the wafer during the die sorter test process, and to measure the assembled product in the socket during the final test process.

  Here, in the conventional method for measuring resistance, both ends of the resistor are connected to a measuring instrument, a voltage is applied to the resistor, and the resistance is obtained from the flowing current value. In the case of this measurement method, since measurement is performed with two terminals, a measurement error occurs when some resistance is attached between the measuring instrument and the resistance (for example, see Patent Document 1).

  For example, contact resistance may accompany the pad and the needle of the measuring instrument for measurement on the wafer, and contact between the assembly product and the pin of the socket for measurement by the socket. As a result, even if the resistance value can be manufactured within the specification, the yield can be lowered due to a test problem.

  As a measuring method not affected by the contact resistance, there is a method of measuring a resistance value with four terminals. In this method of measuring with four terminals, a current is applied between the first and second terminals connected to both ends of the resistance to be measured, and third and fourth terminals separately connected to both ends of the resistance to be measured. Divide the potential difference between them by the applied current. Thereby, the resistance value of the resistance to be measured is obtained.

  In the four-terminal method, no current flows between the third and fourth terminals. Therefore, even if a contact resistance is attached between the third and fourth terminals and the resistance to be measured, the resistance value of the resistance to be measured can be obtained without being influenced by the contact resistance.

However, in the above-described LVDS circuit, in order to apply the four-terminal method, two test input / output terminals are required in addition to the two input / output terminals connected to the termination resistor. Therefore, there is a problem that the number of input / output terminals cannot be reduced.
JP 2004-198168 A

  An object of the present invention is to provide a semiconductor integrated circuit capable of reducing the number of input / output terminals while more accurately measuring the resistance value of a termination resistor.

  A semiconductor integrated circuit according to an embodiment of one aspect of the present invention is a semiconductor integrated circuit for receiving a signal propagated through a transmission line, and includes a logic circuit that performs a logical operation and an output connected to the logic circuit. A differential input receiver circuit for receiving a signal propagated through the transmission line and outputting the signal to the logic circuit; and a non-inverting input terminal and an inverting input terminal of the differential input receiver circuit for impedance matching with the transmission line A termination resistor connected between the first input / output terminal for receiving the signal, the first input / output terminal connected to the non-inverting input terminal of the differential input receiver circuit, and the differential input receiver circuit A second input / output terminal connected to an inverting input terminal for receiving the signal, a first switch circuit connected between a power source and the first input / output terminal, ground, and the second Input and output And a control circuit for controlling on / off of the first switch circuit and the second switch circuit. The control circuit includes: a terminal resistor; In the test operation mode for measuring the resistance value, the first switch circuit and the second switch circuit are turned on, and in the normal operation mode in which the normal operation is performed, the first switch circuit and the second switch circuit. Is turned off.

  A semiconductor integrated circuit according to an embodiment of another aspect of the present invention is a semiconductor integrated circuit for transmitting a signal propagated through a transmission line, and a logic circuit that performs a logical operation and an input connected to the logic circuit A differential output driver circuit for transmitting a signal output from the logic circuit to the transmission line; and a non-inverting output terminal and an inverting output terminal of the differential output driver circuit for impedance matching with the transmission line; A termination resistor connected between the first output terminal and the non-inverting output terminal of the differential output driver circuit, the first input / output terminal for transmitting the signal, and the inversion of the differential output driver circuit. A second input / output terminal connected to the output terminal for transmitting the signal, a first switch circuit connected between a power source and the first input / output terminal, ground, and the second I / O terminal And a control circuit for controlling on / off of the first switch circuit and the second switch circuit, and the control circuit has a resistance value of the termination resistor. In the test operation mode for measuring the first switch circuit, the first switch circuit and the second switch circuit are turned on, and in the normal operation mode for normal operation, the first switch circuit and the second switch circuit are turned off. It is characterized by doing.

  According to the semiconductor integrated circuit of the present invention, it is possible to reduce the number of input / output terminals while measuring the resistance value of the termination resistor more accurately.

  Embodiments according to the present invention will be described below with reference to the drawings.

  FIG. 1 and FIG. 2 are diagrams showing a configuration of a main part of a semiconductor integrated circuit 100 according to a first embodiment which is an aspect of the present invention. FIG. 1 shows a state in which the semiconductor integrated circuit 100 is in a test operation mode to be described later. FIG. 2 shows a state in which the semiconductor integrated circuit 100 is in a normal operation mode to be described later.

  As shown in FIGS. 1 and 2, a semiconductor integrated circuit 100 for receiving a signal transmitted through a transmission line (not shown) includes a logic circuit 1 that performs a logical operation, a differential input receiver circuit 2, and a termination resistor. 3, the first input / output terminal 4, the second input / output terminal 5, the first switch circuit 6, the second switch circuit 7, the first resistor 8, and the second resistor 9. The control circuit 10 is provided.

  The differential input receiver circuit 2 has an output connected to the logic circuit 1, receives a signal propagated through the transmission line, and outputs the signal to the logic circuit 1.

  The termination resistor 3 is connected between the non-inverting input terminal and the inverting input terminal of the differential input receiver circuit 2 for impedance matching with the transmission line. A specification determined as a product is defined for the resistance value of the termination resistor 3. As this specification, for example, a range of 100Ω ± 15Ω is determined.

  The first input / output terminal 4 is connected to a non-inverting input terminal of the differential input receiver circuit 2 so as to receive a signal (a signal is input).

  The second input / output terminal 5 is connected to the inverting input terminal of the differential input receiver circuit 2 so as to receive a signal (a signal is input).

  The first switch circuit 6 is connected between the power supply VDD and the first input / output terminal 4.

  The second switch circuit 7 is connected between the ground GND and the second input / output terminal 5.

  The control circuit 10 controls on / off of the first switch circuit 6 and the second switch circuit 7.

  The first resistor 8 is connected between the first switch circuit 6 and the first input / output terminal 4.

  The second resistor 9 is connected between the second switch circuit 7 and the second input / output terminal 5.

  The first switch circuit 6 and the second switch circuit 7 are preferably analog switch circuits having a low on-resistance because they pass the test current It. In the present embodiment, the first switch circuit 6 and the second switch circuit 7 are each composed of a transistor such as a MOS transistor or a bipolar transistor whose on / off is controlled by a signal input from the control circuit 10.

  As described above, the first and second switch circuits 6 and 7 are each formed of a transistor. However, the first switch circuit 6 is connected to the first input / output terminal 4 via the first resistor 8. The second switch circuit 7 is connected to the second input / output terminal 5 via the second resistor 9.

  For this reason, electrostatic breakdown (ESD) of the transistor can be prevented.

  Here, the operation of the semiconductor integrated circuit 100 having the above-described configuration (method for measuring the termination resistor 3 of the semiconductor integrated circuit 100) will be described.

  In the test operation mode in which the resistance value of the termination resistor 3 is measured, the control circuit 10 turns on the first switch circuit 6 and the second switch circuit 7 as shown in FIG.

  At this time, a path is formed between the power supply VDD and the ground GND so that the test current It flows through the termination resistor 3. Further, the potential difference between both ends of the termination resistor 3 can be measured using the first input / output terminal 4 and the second input / output terminal 5. As a result, the resistance value of the termination resistor 3 can be measured.

That is, in this test operation mode, as shown in the equation (1), the first input / output terminal 4 and the second input / output terminal 5 are generated by the test current It flowing between the power supply VDD and the ground GND. The potential difference ΔV is measured. V1 is a potential measured at the first input / output terminal 4, and V2 is a potential measured at the second input / output terminal 5.

ΔV = V1−V2 Formula (1)

Then, as shown in Expression (2), the resistance value R of the termination resistor 3 is obtained by dividing the potential difference ΔV by the test current It.

R = ΔV / It (2)

  Note that the current value of the test current It depends on the current consumption of the power supply VDD when the first switch circuit 6 and the second switch circuit 7 are turned off, and the first switch circuit 6 and the second switch circuit 7 are turned on. It can be obtained by calculating the difference from the current consumption of the power supply.

  On the other hand, the control circuit 10 turns off the first switch circuit 6 and the second switch circuit 7 as shown in FIG. 2 in the normal operation mode in which the normal operation is performed.

  At this time, the first and second input / output terminals 4 and 5 function as input / output terminals for the differential input receiver circuit 2 to receive a signal transmitted through the transmission line.

  Thus, the semiconductor integrated circuit 100 uses the same terminal in the test operation mode and the normal operation mode. Therefore, the semiconductor integrated circuit 100 can measure the termination resistance with high accuracy without increasing the number of product terminals.

  As described above, according to the semiconductor integrated circuit of this embodiment, it is possible to reduce the number of input / output terminals while measuring the resistance value of the termination resistor more accurately.

  In the first embodiment, the configuration including the differential input receiver circuit that receives the signal transmitted through the transmission line has been described.

  In the second embodiment, an example of a configuration for measuring the resistance value of the termination resistor more accurately will be described.

  FIG. 3 is a diagram illustrating a configuration of a main part of the semiconductor integrated circuit 200 according to the second embodiment which is an aspect of the present invention. FIG. 3 shows the semiconductor integrated circuit 200 in the test operation mode. Further, the normal operation mode state (switch circuit state) of the semiconductor integrated circuit 200 is the same as the normal operation mode state (switch circuit state) of the semiconductor integrated circuit 100 of FIG.

  As shown in FIG. 3, a semiconductor integrated circuit 200 for receiving a signal transmitted through a transmission line (not shown) includes a first current source 11 compared to the semiconductor integrated circuit 100 of the first embodiment, And a second current source 12. Other configurations of the semiconductor integrated circuit 200 are the same as those of the semiconductor integrated circuit 100 of the first embodiment.

  The first current source 11 is connected between the power supply VDD and the first switch circuit 6.

  The second current source 12 is connected between the ground GND and the second switch circuit 7.

  The operation of the semiconductor integrated circuit 200 having the above configuration (method for measuring the termination resistor 3 of the semiconductor integrated circuit 200) is the same as the operation of the semiconductor integrated circuit 100 of the first embodiment (method for measuring the termination resistor 3 of the semiconductor integrated circuit 100). ).

  Therefore, the semiconductor integrated circuit 200 uses the same terminal in the test operation mode and the normal operation mode. Therefore, the semiconductor integrated circuit 200 can measure the termination resistance with high accuracy without increasing the number of product terminals.

  In addition, the first and second current sources 11 and 12 can cause the test current It to flow stably by the termination resistor 3 in the test operation mode. That is, the influence of the fluctuation of the power supply VDD on the test current It can be reduced.

  Therefore, in the test operation mode, the test current It can be made to flow stably by the termination resistor 3, so that the resistance value of the termination resistor 3 can be measured more accurately.

  As described above, according to the semiconductor integrated circuit of this embodiment, it is possible to reduce the number of input / output terminals while measuring the resistance value of the termination resistor more accurately.

  In the second embodiment, an example of a configuration including two current sources in order to measure the resistance value of the termination resistor more accurately has been described. There may be one current source.

  Therefore, in the third embodiment, an example of a configuration provided with one current source for measuring the resistance value of the termination resistor more accurately will be described.

  FIG. 4 is a diagram illustrating a configuration of a main part of a semiconductor integrated circuit 300 according to the third embodiment which is an aspect of the present invention. FIG. 4 shows the semiconductor integrated circuit 300 in the test operation mode. Further, the normal operation mode state (switch circuit state) of the semiconductor integrated circuit 300 is the same as the normal operation mode state (switch circuit state) of the semiconductor integrated circuit 100 of FIG.

  As shown in FIG. 4, the semiconductor integrated circuit 300 for receiving a signal transmitted through a transmission line (not shown) further includes a current source 11 as compared with the semiconductor integrated circuit 100 of the first embodiment. Other configurations of the semiconductor integrated circuit 300 are the same as those of the semiconductor integrated circuit 100 of the first embodiment.

  The current source 11 is connected between the power supply VDD and the first switch circuit 6.

  The operation of the semiconductor integrated circuit 300 having the above configuration (the method for measuring the termination resistor 3 of the semiconductor integrated circuit 300) is the same as the operation of the semiconductor integrated circuit 100 of the first embodiment (the method for measuring the termination resistor 3 of the semiconductor integrated circuit 100). ).

  Therefore, the semiconductor integrated circuit 300 uses the same terminal in the test operation mode and the normal operation mode. Therefore, the semiconductor integrated circuit 300 can measure the termination resistance with high accuracy without increasing the number of product terminals.

  In addition, the current source 11 allows the test current It to flow stably by the termination resistor 3 in the test operation mode. That is, the influence of the fluctuation of the power supply VDD on the test current It can be reduced.

  Therefore, in the test operation mode, the test current It can be made to flow stably by the termination resistor 3, so that the resistance value of the termination resistor 3 can be measured more accurately.

  As described above, according to the semiconductor integrated circuit of this embodiment, it is possible to reduce the number of input / output terminals while measuring the resistance value of the termination resistor more accurately.

  In the third embodiment, an example of a configuration including one current source for measuring the resistance value of the termination resistor more accurately has been described.

  In the fourth embodiment, another example in which one current source is provided in order to more accurately measure the resistance value of the termination resistor will be described.

  FIG. 5 is a diagram illustrating a configuration of a main part of a semiconductor integrated circuit 400 according to the fourth embodiment which is an aspect of the present invention. FIG. 5 shows the semiconductor integrated circuit 400 in the test operation mode. The normal operation mode state (switch circuit state) of the semiconductor integrated circuit 400 is the same as the normal operation mode state (switch circuit state) of the semiconductor integrated circuit 100 of FIG.

  As shown in FIG. 5, the semiconductor integrated circuit 400 for receiving a signal transmitted through a transmission line (not shown) further includes a current source 12 as compared with the semiconductor integrated circuit 100 of the first embodiment. Other configurations of the semiconductor integrated circuit 400 are the same as those of the semiconductor integrated circuit 100 of the first embodiment.

  The current source 12 is connected between the ground GND and the second switch circuit 7.

  The operation of the semiconductor integrated circuit 400 having the above-described configuration (method of measuring the termination resistor 3 of the semiconductor integrated circuit 400) is the same as the operation of the semiconductor integrated circuit 100 of the first embodiment (method of measuring the termination resistor 3 of the semiconductor integrated circuit 100). ).

  Therefore, the semiconductor integrated circuit 400 uses the same terminal in the test operation mode and the normal operation mode. Therefore, the semiconductor integrated circuit 400 can measure the termination resistance with high accuracy without increasing the number of product terminals.

  In addition, the current source 12 allows the test current It to flow stably by the termination resistor 3 in the test operation mode. That is, the influence of the fluctuation of the power supply VDD on the test current It can be reduced.

  Therefore, in the test operation mode, the test current It can be made to flow stably by the termination resistor 3, so that the resistance value of the termination resistor 3 can be measured more accurately.

  As described above, according to the semiconductor integrated circuit of this embodiment, it is possible to reduce the number of input / output terminals while measuring the resistance value of the termination resistor more accurately.

  In the first to fourth embodiments, the configuration including the differential input receiver circuit that receives the signal transmitted through the transmission line has been described.

  In this embodiment, a configuration having a differential output driver circuit that transmits (outputs) a signal to be propagated to a transmission line will be described.

  6 and 7 are diagrams showing the configuration of the main part of a semiconductor integrated circuit 500 according to the fifth embodiment which is an aspect of the present invention. FIG. 6 shows a state in which the semiconductor integrated circuit 500 is in a test operation mode to be described later. FIG. 7 shows a state in which the semiconductor integrated circuit 500 is in a normal operation mode to be described later. In the figure, the same reference numerals as those in the first embodiment indicate the same configurations as those in the first embodiment.

  As shown in FIGS. 6 and 7, a semiconductor integrated circuit 500 for transmitting a signal to be propagated to a transmission line (not shown) includes a logic circuit 1 that performs a logical operation, a differential output driver circuit 502, and a termination resistor. 503, a first input / output terminal 504, a second input / output terminal 505, a first switch circuit 6, a second switch circuit 7, a first resistor 8, and a second resistor 9. The control circuit 10 is provided.

  The differential output driver circuit 502 has an input connected to the logic circuit 1 and transmits a signal output from the logic circuit 1 to the transmission line.

  The termination resistor 503 is connected between the non-inverting input terminal and the inverting input terminal of the differential output driver circuit 502 in order to match impedance with the transmission line. A specification determined as a product is defined for the resistance value of the termination resistor 503. As this specification, for example, a range of 100Ω ± 15Ω is determined.

  The first input / output terminal 504 is connected to the non-inverting input terminal of the differential output driver circuit 502 and transmits a signal (a signal is output).

  The second input / output terminal 505 is connected to the inverting input terminal of the differential output driver circuit 502 so as to transmit a signal (a signal is output).

  The first switch circuit 6 is connected between the power supply VDD and the first input / output terminal 504.

  The second switch circuit 7 is connected between the ground GND and the second input / output terminal 505.

  The control circuit 10 controls on / off of the first switch circuit 6 and the second switch circuit 7.

  The first resistor 8 is connected between the first switch circuit 6 and the first input / output terminal 504.

  The second resistor 9 is connected between the second switch circuit 7 and the second input / output terminal 505.

  Since the first switch circuit 6 and the second switch circuit 7 pass the test current It as in the first embodiment, it is desirable that the first switch circuit 6 and the second switch circuit 7 be analog switch circuits with low on-resistance. In the present embodiment, the first switch circuit 6 and the second switch circuit 7 are each composed of a transistor such as a MOS transistor or a bipolar transistor whose on / off is controlled by a signal input from the control circuit 10.

  As described above, the first and second switch circuits 6 and 7 are each formed of a transistor. However, the first switch circuit 6 is connected to the first input / output terminal 504 via the first resistor 8. The second switch circuit 7 is connected to the second input / output terminal 505 via the second resistor 9.

  Therefore, electrostatic breakdown (ESD) or the like of the transistor can be prevented.

  As described above, the semiconductor integrated circuit 500 basically has the same configuration as the semiconductor integrated circuit 100 of the first embodiment except that the differential input receiver circuit 2 is replaced with the differential output driver circuit 502.

  Here, the operation of the semiconductor integrated circuit 500 having the above-described configuration (method for measuring the termination resistor 503 of the semiconductor integrated circuit 500) will be described.

  In the test operation mode in which the resistance value of the termination resistor 503 is measured, the control circuit 10 turns on the first switch circuit 6 and the second switch circuit 7 as shown in FIG.

  At this time, a path for allowing the test current It to flow through the termination resistor 503 is formed between the power supply VDD and the ground GND. Further, the potential difference between both ends of the termination resistor 503 can be measured using the first input / output terminal 504 and the second input / output terminal 505. As a result, the resistance value of the termination resistor 503 can be measured.

  That is, in this test operation mode, as shown in the above-described equation (1), the first input / output terminal 504 and the second input are generated by the test current It flowing between the power supply VDD and the ground GND. A potential difference ΔV with respect to the output terminal 505 is measured. In this embodiment, V1 is a potential measured at the first input / output terminal 504, and V2 is a potential measured at the second input / output terminal 505.

  Then, as shown in Equation (2), the resistance value R of the termination resistor 503 is obtained by dividing the potential difference ΔV by the test current It.

  As in the first embodiment, the current value of the test current It is the current consumption of the power supply VDD when the first switch circuit 6 and the second switch circuit 7 are turned off, the first switch circuit 6 and the first switch circuit 6. It can be obtained by obtaining the difference from the current consumption of the power supply when the switch circuit 7 of 2 is turned on.

  On the other hand, the control circuit 10 turns off the first switch circuit 6 and the second switch circuit 7 in the normal operation mode in which the normal operation is performed, as shown in FIG.

  At this time, the first and second input / output terminals 504 and 505 function as input / output terminals for transmitting the signal output from the differential output driver circuit 502 to the transmission line.

  As described above, the semiconductor integrated circuit 500 uses the same terminals in the test operation mode and the normal operation mode, as in the first embodiment. For this reason, the semiconductor integrated circuit 500 can measure the termination resistance with high accuracy without increasing the number of terminals of the product as in the first embodiment.

  As described above, according to the semiconductor integrated circuit of this embodiment, it is possible to reduce the number of input / output terminals while measuring the resistance value of the termination resistor more accurately.

  In the fifth embodiment, similarly to the second to fourth embodiments, a current source may be added to measure the resistance value of the termination resistor more accurately.

It is a figure which shows the principal part structure of the semiconductor integrated circuit 100 which concerns on Example 1 which is 1 aspect of this invention. It is a figure which shows the principal part structure of the semiconductor integrated circuit 100 which concerns on Example 1 which is 1 aspect of this invention. It is a figure which shows the structure of the principal part of the semiconductor integrated circuit 200 which concerns on Example 2 which is 1 aspect of this invention. It is a figure which shows the structure of the principal part of the semiconductor integrated circuit 300 which concerns on Example 3 which is 1 aspect of this invention. It is a figure which shows the structure of the principal part of the semiconductor integrated circuit 400 which concerns on Example 4 which is 1 aspect of this invention. It is a figure which shows the structure of the principal part of the semiconductor integrated circuit 500 concerning Example 5 which is 1 aspect of this invention. It is a figure which shows the structure of the principal part of the semiconductor integrated circuit 500 concerning Example 5 which is 1 aspect of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Logic circuit 4,504 First input / output terminal 5,505 Second input / output terminal 2 Differential input receiver circuit 3,503 Termination resistor 6 First switch circuit 7 Second switch circuit 8 First resistor 9 Second resistor 10 Control circuit 11 First current source 12 Second current source 100, 200, 300, 400, 500 Semiconductor integrated circuit 502 Differential output driver circuit

Claims (5)

A semiconductor integrated circuit for receiving a signal propagated through a transmission line,
A logic circuit for performing a logical operation;
A differential input receiver circuit connected to the logic circuit for receiving a signal propagated through the transmission line and outputting the signal to the logic circuit;
In order to perform impedance matching with the transmission line, a termination resistor connected between a non-inverting input terminal and an inverting input terminal of the differential input receiver circuit;
A first input / output terminal connected to the non-inverting input terminal of the differential input receiver circuit for receiving the signal;
A second input / output terminal connected to the inverting input terminal of the differential input receiver circuit for receiving the signal;
A first switch circuit connected between a power supply and the first input / output terminal;
A second switch circuit connected between ground and the second input / output terminal;
A control circuit for controlling on / off of the first switch circuit and the second switch circuit,
The control circuit includes:
In the test operation mode for measuring the resistance value of the termination resistor, the first switch circuit and the second switch circuit are turned on,
In a normal operation mode in which a normal operation is performed, the first switch circuit and the second switch circuit are turned off. A first resistor connected between the first switch circuit and the first input / output terminal;
A second resistor connected between the second switch circuit and the second input / output terminal;
2. The semiconductor integrated circuit according to claim 1, wherein each of the first switch circuit and the second switch circuit includes a transistor whose on / off is controlled by a signal input from the control circuit. circuit. The current source is connected between at least one of the power source and the first switch circuit, or between the ground and the second switch circuit. The semiconductor integrated circuit as described. A semiconductor integrated circuit for transmitting a signal propagated through a transmission line,
A logic circuit for performing a logical operation;
A differential output driver circuit for connecting an input to the logic circuit and transmitting a signal output from the logic circuit to the transmission line;
A termination resistor connected between the non-inverting output terminal and the inverting output terminal of the differential output driver circuit for impedance matching with the transmission line;
A first input / output terminal for transmitting the signal, connected to the non-inverting output terminal of the differential output driver circuit;
A second input / output terminal connected to the inverting output terminal of the differential output driver circuit for transmitting the signal;
A first switch circuit connected between a power supply and the first input / output terminal;
A second switch circuit connected between ground and the second input / output terminal;
A control circuit for controlling on / off of the first switch circuit and the second switch circuit,
The control circuit includes:
In the test operation mode for measuring the resistance value of the termination resistor, the first switch circuit and the second switch circuit are turned on,
In a normal operation mode in which a normal operation is performed, the first switch circuit and the second switch circuit are turned off. During the test operation mode, a potential difference between the first input / output terminal and the second input / output terminal caused by a test current flowing between the power supply and the ground is measured;
The semiconductor integrated circuit according to claim 1, wherein a resistance value of the termination resistor is obtained by dividing the potential difference by a current value of the test current.

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