JPH02181674A - Method for inspecting analog switch integrated circuit - Google Patents

Abstract

PURPOSE:To perform inspection without any external parts by using the pin switching function of a tester and setting input signal terminals for analog signals and signals of control circuits according to the purpose of measurement. CONSTITUTION:For example, when a source current is measured, the pin switching function of the tester which has a switch matrix is used. The input signal terminals of analog switches S1 - S9 and the control signals of the control circuits C1 - C6 are set to a current measurement state. Then individual characteristics are measured by a power source VCC terminal to measure the source current without any external parts. Thus, no external parts for the input/output terminals of the switches S1 - S9 is required, so a special measuring jig is not necessary. Even if terminal positions are different, the current can be measured by utilizing the pin switching function. Further, the characteristics of the switches S1 - S9 are measured directly, so characteristic variation which causes a function defect is detected in advance.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for testing an analog switch integrated circuit, and in particular, a method for testing the functionality of an analog switch integrated circuit and testing the characteristics of circuit elements inside the analog switch integrated circuit. It relates to an inspection method performed by measurement.

[Conventional technology]

Conventionally, the characteristics of analog switch integrated circuits are measured by testing the entire circuit as one function. Therefore, depending on the type of measurement, various external components are required depending on the circuit configuration.

Also, even with analog switch integrated circuits with the same circuit configuration,
If the positions of the input/output signal terminals are different, it is necessary to use a measurement jig with the same external parts for each position of the input/output signal terminal, or to use a pin conversion adapter for functional testing. be. For this reason, even if a programmable tester or the like having a switch matrix function capable of switching pins under program control is used, the pin switching function of the tester cannot be effectively utilized.

In addition, in such tests, the entire circuit is measured as one function, so the measurement result can only be determined as a malfunction of the entire circuit. Therefore, the individual characteristics of each analog switch in an analog switch integrated circuit remains unknown, and even in the case of malfunction, the cause cannot be directly determined from the measurement results. A specific example of this type of analog switch integrated circuit will be explained.

FIG. 4 is a circuit diagram showing a specific example of an analog switch integrated circuit used in a subscriber circuit of a digital exchange.

This analog switch integrated circuit is located between a subscriber line and an exchange, and has functions such as supplying talking current to subscriber telephones, sending out ringing signals, and testing subscriber lines. It is. This analog switch integrated circuit includes a plurality of analog switches and a control circuit for controlling each analog switch.

In FIG. 4, the analog switch integrated circuit 10 has P
It is mainly composed of analog switches 81 to S9 using NPN elements. Analog switches 81 to S9 here
The blacked out parts are gate turn-offs (
AA, which indicates an analog switch with GTO) functionality;
BB, B, C.

Terminals labeled D, A, RA, RB, NTI, and NTO are input/output signal terminals of the analog switch integrated circuit, respectively. In addition, the blocks labeled 0N10FF are control circuits 01 to 01 that respectively control the analog switches 81 to S9 to turn on or off.
It is C3. The control circuit C1 that controls the analog switch S9 is controlled by a signal from the control signal input terminal PLP. The control circuit C2 that controls the analog switches 81 to S6 has control signal input terminals RNG and REV.

Controlled by signals from NOR and GTO. Further, the control circuit C3 that controls the analog switches 87 to S8 is controlled by a signal from the control signal input terminal NTC. Further, the analog switch integrated circuit 10 is provided with a first power terminal VCC, a second power terminal VEE, and a ground terminal E in order to supply other driving power.

Thereby, the analog switch integrated circuit 10 has a function of turning each analog switch on or off by setting the control signal input terminals of the control circuits 01 to C3 to high or low level. That is, the relationship between each control signal input terminal and the on state and off state of each analog switch is designed to be as shown in Table 1 below.

αKF This page margin) Table 1 The method of testing the quality of analog switch integrated circuits as described above takes into account the functions performed by the entire analog switch integrated circuit under actual usage conditions, simulates actual usage conditions, and evaluates the characteristics. We carry out inspection methods that measure the following:

An example of a measurement circuit for testing a specific analog switch integrated circuit that measures eight states in actual use is shown in the fifth section.
As shown in the figure. Further, Table 2 shows a table showing the measurement procedure.

FIG. 5 of Table 2 is a measurement circuit diagram illustrating a measurement method for testing an analog switch integrated circuit by measuring eight states in actual use.

This measurement method uses a measurement circuit as shown in FIG. 5 to first set each control signal input terminal to a low level (L) or a high level ( H), by setting the switches SWI to SW5 to the ON state or OFF state, respectively, and reading the current values of the ammeters A1 to A5 connected to the input/output signal terminals. Next, each ammeter A1 to A5 read
Compare the current value with the current value in the specification column of Table 2.

Determine malfunction.

[Problem to be solved by the invention]

However, in the measurement method described above, the second
As is clear from the circuit diagram in the figure, it is necessary to add resistances used in actual use and switch circuits for switching circuit states as external components of the integrated circuit. It is necessary to place both ends away from the ground potential.

Therefore, this measurement method has a problem in that a dedicated measurement jig and measurement program are required for each circuit configuration.

Furthermore, even if the configuration of the measurement circuit is the same, if the positions of the input/output signal terminals are different, it is necessary to prepare separate measurement jigs in response to this difference.

The present invention has been made to solve the above problems.

An object of the present invention is to provide a testing method that can test analog switch integrated circuits without connecting external components to input/output signal terminals.

Another object of the present invention is that even if the analog switch integrated circuits have the same circuit configuration but different input/output signal terminals, the analog switch integrated circuits can be used without using separate measurement jigs and separate measurement programs. The objective is to provide an inspection method that can be used for inspection.

Another object of the present invention is to provide an inspection method capable of determining characteristic variations of individual analog switches in an analog switch integrated circuit.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Means to solve the problem]

In order to achieve the above object, a method for testing an analog switch integrated circuit according to the present invention includes a plurality of analog switches, a control circuit that controls the on/off state of the analog switches, an input/output signal terminal, and the control circuit. In an analog switch integrated circuit having a control signal terminal for supplying a control signal to the input/output signal terminal, the characteristics of each analog switch can be measured and the analog switch integrated circuit can be tested without connecting external components to the input/output signal terminal. shall be.

The present invention also provides a testing method for testing an analog switch integrated circuit having a plurality of analog switches, a control circuit that controls the on/off state of the analog switch, an input/output signal terminal, and a control signal terminal that supplies the control circuit. Is it a current source? l! Equipped with signal supply devices such as pressure sources and signal sources, and signal detection devices such as voltmeters, ammeters, and detectors, only the input/output signal terminals and control signal terminals corresponding to each analog switch to be measured are required for measurement. It is possible to connect a signal supply device and a signal detection device, measure the characteristics of each analog switch, and test the analog switch integrated circuit without connecting external components to other input/output signal terminals of the analog switch integrated circuit. Features.

[Effect]

According to the above-mentioned means, in an analog switch integrated circuit having a plurality of analog switches, a control circuit for controlling the on/off state of the analog switches, an input/output signal terminal, and a control signal terminal for supplying the control signal to the control circuit. The analog switch integrated circuit is tested by measuring the characteristics of each analog switch without connecting any external parts to the input/output signal terminals. In other words, in the present invention, an analog switch integrated circuit is inspected by testing the entire circuit in one test.
Analog switch integrated circuits are tested by directly measuring the characteristics of each individual analog switch in the integrated circuit rather than measuring them as a single function. This eliminates the need for all external components for input/output signal terminals, which are always required in normal inspection methods.

Furthermore, with this testing method, it is not necessary to prepare a special measuring jig for each circuit configuration of the analog switch integrated circuit, and measurement can be easily performed by simply changing the measurement program.

(Example) Hereinafter, an example of the present invention will be specifically described using the drawings.

In general, the input/output signal terminals and control signal terminals of analog switches in analog switch integrated circuits are usually directly exposed outside the package as external terminals due to the characteristics of the analog switch or for reasons of its application. .

Therefore, the characteristics of each analog switch in the analog switch integrated circuit can be directly measured without being directly related to the functions performed by the five circuits as a whole. Therefore, in the testing method of this embodiment, the characteristics of each analog switch in the analog switch integrated circuit are directly measured.

1, 2, and 3 show examples of respective measurement circuits when the method for testing analog switch integrated circuits according to this embodiment is applied to testing analog switch integrated circuits for subscriber circuits. It is a circuit diagram.

FIG. 1 is a circuit diagram for measuring the power supply current of an analog switch integrated circuit. The configuration of this measurement circuit uses, for example, the pin switching function of a tester that has a switch matrix connected to the analog switch integrated circuit under test, and the signals at the input signal terminal of the analog switch and the control signal input terminal of each control circuit. The settings are set to the power supply current measurement state as shown, and the current at the vCC terminal is measured. This makes it possible to measure power supply current without any external components.

The power supply current measurement state here is a state in which the control signal input terminal NOR is set to a high level, the analog switches S3 and S4 are turned on, and calls by the subscriber are monitored. Note that in this measurement, all other control signal input terminals are set to low level (ground level). Further, the power supply current measurement state may be a state in which the subscriber is in a telephone conversation state and a telephone current is flowing through the analog switches 83 and 84, but even if the measurement is performed in that state.

By connecting the current sources of the tester to the B terminal and the A terminal, respectively, and flowing a geometrical communication current, external parts can be made unnecessary.

FIG. 2 is a circuit diagram for measuring leakage current of an analog switch integrated circuit. The measurement circuit in this case is a measurement circuit that measures the off state of the analog switch. In this measurement circuit.

After setting all control signal input terminals to low level.

This measurement circuit applies -100v to the output signal side terminal (B terminal) of analog switch S3, and applies +100v to the input signal side terminal (BB terminal) of analog switch S3 to measure leakage current. . To test the OFF state of an analog switch, it is only necessary to determine the current blocking ability of each analog switch when the switch is OFF, and as shown in the figure, it can be easily measured without any external parts.

Moreover, FIG. 3 is a circuit diagram when measuring the on-voltage of an analog switch integrated circuit. The measurement circuit in this case is a measurement circuit that measures the on state of the analog switch. In this measurement circuit, for example, after setting each control signal input terminal to a high level or a low level so that the analog switch S3 is turned on, a current source of a tester is connected to the analog switch S3, and a specified current value is set. The circuit flows through the terminal and measures the voltage at its terminals.

The ON state of the analog switch can also be tested without any external components by setting the control signal input terminal and connecting a current source to the analog switch input/output signal terminal as shown in the figure.

In this way, by focusing on individual analog switches and measuring their characteristics using the tester's bin switching function, it is possible to test analog switch integrated circuits without using external components. be.

Also, 1 unit can be used as a measurement unit connected to the input/output signal terminal.
By using an oscillator and pulser, AC characteristics and transient characteristics can also be measured without external components.

The main points of this embodiment described above can be summarized as follows.

(1) an analog switch, a control circuit that controls the on/off state of the analog switch, and an input/output signal terminal;
This is a testing method for testing an analog switch integrated circuit having a control signal terminal that supplies the control circuit.

(2) For example, a signal supply device such as a current source, voltage source, or signal source, and a signal detection device such as a voltmeter, ammeter, or detector are placed on the port side of a switch matrix that has a terminal switching function, and the switch Place the analog switch integrated circuit to be measured on the pin side of the matrix.

(3) For inspection, connect the signal supply device and signal detection device necessary for characteristic measurement only to the input/output signal terminals and control signal terminals corresponding to the analog switch whose characteristics are to be measured. To measure the characteristics of an analog switch without connecting any external components to other input/output signal terminals.

The present invention has been specifically explained above based on examples, but
It goes without saying that the present invention is not limited to the embodiments described above, and can be modified in various ways without departing from the spirit thereof.

〔Effect of the invention〕

As described above, according to the method for testing an analog switch integrated circuit of the present invention, there is no need for external parts to be attached to the input/output signal terminals, so there is no need to prepare a special measurement jig.
Therefore, it is possible to easily measure 41-multiplex circuits having the same circuit configuration with different positions of input/output signal terminals using the same measurement program that takes advantage of the pin switching function of the tester. Furthermore, since the characteristics of each analog switch are directly measured, the cause of malfunction can be determined. For example, when measuring the characteristics over time of an analog switch integrated circuit, 1 the cause of a malfunction can be directly known from variations in the characteristics of individual analog switches before the malfunction occurs.

[Brief explanation of the drawing]

1, 2, and 3 show examples of respective measurement circuits when the method for testing analog switch integrated circuits according to this embodiment is applied to testing analog switch integrated circuits for subscriber circuits. FIG. 4 is a circuit diagram showing a specific example of an analog switch integrated circuit used in a subscriber circuit of a digital exchange. FIG. 5 is a measurement circuit diagram illustrating a measurement method for testing an analog switch integrated circuit by measuring eight states in actual use. In the figure, 10...analog switch integrated circuit, 81-S
9...Analog switch, AA, BB, B, C. D, A, RA, RB, NTI, NTO...input/output signal terminals, 01-C3...control circuit, PLP, RNG. REV, NOR, GTO, NTC--control signal input terminal, VCC--first power supply terminal. terminal. E...Ground terminal. VEE...Second power supply

Claims (2)

[Claims] (1) In an analog switch integrated circuit having a plurality of analog switches, a control circuit that controls the on/off state of the analog switch, an input/output signal terminal, and a control signal terminal that supplies the control circuit, the input/output A method for testing an analog switch integrated circuit, characterized by measuring the characteristics of each analog switch and testing the analog switch integrated circuit without connecting external components to signal terminals. (2) An inspection method for inspecting an analog switch integrated circuit having a plurality of analog switches, a control circuit that controls the on/off state of the analog switches, an input/output signal terminal, and a control signal terminal that supplies the control circuits. It is equipped with signal supply devices such as current sources, voltage sources, and signal sources, and signal detection devices such as voltmeters, ammeters, and detectors, and has input/output signal terminals and control signals corresponding to each analog switch to be measured. Connect only the signal supply device and signal detection device necessary for measurement to the terminal, and measure the characteristics of each analog switch without connecting external components to other input/output signal terminals of the analog switch integrated circuit. A method for testing an analog switch integrated circuit, the method comprising testing an integrated circuit.