JPH083517B2 - Semiconductor integrated circuit device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] For example, a semi-custom LSI (large scale integrated circuit) in which a configuration convenient for testing an operational amplifier is incorporated is provided.
uit) type semiconductor integrated circuit device, the purpose is to make it possible to easily test a single operational amplifier mounted in the semiconductor integrated circuit device with a voltage follower configuration and to easily cancel the configuration. And a single operational amplifier mounted on a semiconductor chip in which a logic circuit portion is built, and the operational amplifier having a negative side analog signal input terminal and an analog signal output terminal arranged in parallel and closed. If the operational amplifier is
A switch having a follower configuration and a control terminal drawn out for performing on / off control of the switch are provided.

[Industrial applications]

The present invention is, for example, a semi-custom LSI (large scale integ
rated circuit) type semiconductor integrated circuit device.

In general, a gate array, which is a type of custom LSI, is often composed of only digital circuits, and analog circuits have been supported by standard cells.

However, in recent years, shortening the development period and shortening the delivery time have also been required for mounting analog circuits.

Therefore, it is possible to mount an analog circuit on the gate array.

[Conventional technology]

Conventionally, CMOS equipped with an operational amplifier that is an analog circuit
(Complementary metal oxide semiconductor) There is no practical gate array.

A standard cell is known as a semiconductor integrated circuit device in which a digital circuit and an analog circuit are mixedly mounted.

FIG. 4 shows an explanatory diagram of a main circuit for explaining the standard cell.

In the figure, 1 is an integrated circuit chip, 2 is a logic circuit part, 3A and 3B are operational amplifiers, 4 is a logic circuit input terminal, 5
Is a logic circuit output terminal, 6 is an analog signal input terminal, and 7 is an analog signal output terminal.

As is clear from the figure, the analog circuits, that is, the operational amplifiers 3A, 3B, etc. are built in a circuit-connected state.

[Problems to be Solved by the Invention]

The semiconductor integrated circuit device shown in FIG. 4 has various problems, which are exemplified as follows.

(1) It takes a long development period and the number of processes increases.
The reason is that, when laying out analog circuits, it is impossible to automatically design everything with a computer, and it is necessary to perform work manually.

In recent years, the product cycle is very fast, so shortening the development period and the prototype period has become an important issue.

(2) In order to ship the manufactured semiconductor integrated circuit device, it is necessary to test the analog circuit for each type of the semiconductor integrated circuit device, which requires a lot of man-hours for testing, and the period required for this is extremely long.

From this, for example, when the operational amplifier is mounted on the CMOS gate array, it is considered preferable to mount the operational amplifier alone without making a complicated circuit configuration.

FIG. 5 shows a circuit diagram of an essential part of a semiconductor integrated circuit device according to the above idea. The same symbols as those used in FIG. 4 indicate the same parts or have the same meanings.

In the figure, 6A and 6B are + side analog signal input terminal and-side analog signal input terminal, 7A in the operational amplifier 3A.
Is the analog signal output terminal of the operational amplifier 3A, 6C and
Reference numeral 6D shows a + side analog signal input terminal and a-side analog signal input terminal in the operational amplifier 3B, and 7B shows an analog signal output terminal in the operational amplifier 3B.

As shown in Fig. 5, when the operational amplifiers are mounted alone, they can be handled in the same way as logic circuits and can be laid out by automatic wiring by a computer, significantly shortening the development period. can do.

However, a problem remains when the operational amplifier is mounted alone as described above. That is, the semiconductor integrated circuit device is
It is necessary to perform a shipping test without fail, but when the operational amplifier is mounted alone, it is impossible to confirm the operation as it is because it is in an open loop state, as is clear from the figure. .

FIG. 6 is a circuit diagram of an essential part for explaining a null amplifier method that has been used to test the operation of a single operational amplifier.

As can be seen from the figure, the single operational amplifier DUT under test
In addition to the auxiliary amplifier Null, many external components such as resistors, capacitors and switches must be used.

Usually, when testing a semiconductor integrated circuit device, the test is first performed in the state of a wafer, and then the one that is diced and mounted in a package is tested. Even in the semiconductor integrated circuit device in which the operational amplifier is built, of course, since it is performed in the state of being mounted in the package, a test board is required for that, and moreover,
The test board must be created for each type of semiconductor integrated circuit device. The reason is that the input / output terminals of the operational amplifier are different for each type.

FIG. 7 is a circuit diagram of an essential part for explaining a circuit configuration suitable for testing a single operational amplifier.

As can be seen from the figure, it is the simplest to test by configuring the so-called voltage follower by connecting the negative side analog signal input terminal 6B and the analog signal output terminal 7A of the operational amplifier 3A for feedback. .

Therefore, when the operational amplifier 3A or 3B in the semiconductor integrated circuit device described with reference to FIG. 5 is tested with the voltage follower configuration, the operational amplifier 3A or 3B on the test board is It is necessary to connect the side analog signal input terminal 6B and the analog signal output terminal 7A, or connect the-side analog signal input terminal 6D and the analog signal output terminal 7B.

FIG. 8 is an explanatory diagram of a main circuit for explaining a case where the single operational amplifiers 3A and 3B in the semiconductor integrated circuit device described with reference to FIG. 5 have a voltage follower configuration. The same symbols as those used above indicate the same parts or have the same meanings.

In the figure, L _V1 and L _V2 indicate wiring on the test board.

Even in such a case, since the input / output terminals of the operational amplifier differ depending on the product type, it is necessary to create a test board corresponding to it.

The present invention intends to make a single operational amplifier mounted on a semiconductor integrated circuit device into a voltage follower configuration simply for testing, and to make it possible to release the configuration easily.

[Means for solving the problem]

In the semiconductor integrated circuit device according to the present invention, a single operational amplifier (for example, operational amplifier 3A or 3B) mounted on an integrated circuit chip (for example, integrated circuit chip 1) in which a logical circuit portion (for example, logical circuit portion 2) is built. Etc.) and the − side analog signal input terminal (for example, − side analog signal input terminal 6B or 6D) and the analog signal output terminal (for example, analog signal output terminal 7A or 7B) in the operational amplifier. When the switch is closed, the switch (for example, switch SW) that makes the operational amplifier a voltage follower configuration.
1 or SW2, etc.) and a control terminal (for example, control terminal 8) drawn out for performing on / off control of the switch.

[Action]

By adopting the above means, the single operational amplifier mounted on the semiconductor integrated circuit device can be easily made into the voltage follower configuration, or the voltage follower configuration can be released in the same manner, thus facilitating the test. In addition, it is possible to carry out the tests in a unified manner, and it is possible to use a general-purpose test board, which is effective in shortening the development period and the cost and reducing the cost.

〔Example〕

FIG. 1 is a circuit diagram of a main part for explaining a semiconductor integrated circuit device according to an embodiment of the present invention. The same symbols as those used in FIGS. 4 to 8 indicate the same parts or They have the same meaning.

In the figure, SW1 and SW2 are analog switches for forming and releasing a voltage follower, and 8 is a control terminal (test terminal) for controlling the analog switches SW1 and SW2, respectively.

FIG. 2 is an explanatory view of an essential part circuit showing, in an enlarged manner, a cell-forming portion as one operational amplifier in the embodiment shown in FIG. 1, and is the same as the symbol used in FIG. Symbols indicate the same part or have the same meaning.

FIG. 3 is a more detailed circuit diagram of the essential parts of the cell-shaped portion shown in FIG. 2, and the same symbols as those used in FIGS. 1 and 2 indicate the same portions, or They have the same meaning.

In the figure, Q1 is a p-channel MOS (metal insulator s
semiconductor transistor, Q2 is an n-channel MOS transistor, Q3 is an n-channel MOS transistor, and Q4 is an n-channel MOS transistor.

In the embodiment of the present invention shown in FIGS. 1 to 3, the switches SW1 and SW2 are normally off, that is, the operational amplifiers 3A and 3B are in the open loop, and the switch SW1 is only in the test. And SW2 are turned on, that is, the operational amplifiers 3A and 3B are closed loop.

Now, in order to test the operational amplifiers 3A and 3B, by applying "1" to the control terminal 8 to turn on the switches SW1 and SW2, a voltage follower configuration is achieved, and then the + side analog input terminal 6A , And 6C, and measure the voltage at the analog output terminals 7A and 7B. Also, after the test is completed, it goes without saying that the control terminal 8 is set to "0" and the switches SW1 and SW2 are turned off to cancel the voltage follower configuration.
By connecting an external circuit, it immediately functions as an operational amplifier.

The analog switches SW1 and SW2 may be composed of a single transistor.

〔The invention's effect〕

In a semiconductor integrated circuit device according to the present invention, a single operational amplifier mounted on an integrated circuit chip in which a logic circuit portion is built, a negative analog signal input terminal and an analog signal output in the operational amplifier. It is provided with a switch that is arranged in parallel with the terminal and has a voltage follower configuration when the operational amplifier is closed, and a control terminal that is drawn out to perform on / off control of the switch. .

By adopting the above configuration, the single operational amplifier mounted on the semiconductor integrated circuit device can be easily made into the voltage follower configuration, or the voltage follower configuration can be canceled in the same manner, thus facilitating the test. In addition, it is possible to carry out the tests in a unified manner, and it is possible to use a general-purpose test board, which is effective in shortening the development period and the cost and reducing the cost.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a main circuit for explaining a semiconductor integrated circuit device according to an embodiment of the present invention, and FIG. 2 shows a portion for forming a cell as one operational amplifier in the embodiment shown in FIG. FIG. 3 is an enlarged schematic diagram of the main circuit, FIG. 3 is a more detailed schematic diagram of the main circuit of the cell-shaped portion shown in FIG.
FIG. 5 is an explanatory view of a main circuit for explaining a standard cell, FIG. 5 is an explanatory view of a main circuit of a semiconductor integrated circuit device equipped with an operational amplifier alone, and FIG. 6 is a test of operation of the operational amplifier alone. FIG. 8 is an explanatory diagram of a main circuit for explaining the null amplifier method used in FIG. 7, and FIG. 7 is an explanatory diagram of a main circuit for explaining a circuit configuration suitable for testing a single operational amplifier. The figures respectively show schematic diagrams of the main circuits for explaining the case where the single operational amplifiers 3A and 3B in the semiconductor integrated circuit device described with reference to FIG. 5 have a voltage follower configuration. In the figure, 1 is an integrated circuit chip, 2 is a logic circuit part,
3A and 3B are operational amplifiers, 4 is a logic circuit input terminal, 5 is a logic circuit output terminal, 6 is an analog signal input terminal, 6A and
6B is a + side analog signal input terminal and a − side analog signal input terminal in the operational amplifier 3A, 6C and 6D are + side analog signal input terminals and a − side analog signal input terminal in the operational amplifier 3B, and 7 is an analog signal. Output terminal, 7A is an analog signal output terminal in the operational amplifier 3A, 7B is an analog signal output terminal in the operational amplifier 3B, 8 is a control terminal,
SW1 and SW2 are analog switches for forming and releasing the voltage follower, respectively.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location H01L 21/822 27/04 H01L 27/04 T (72) Inventor Seiichi Hasegawa Nakahara, Kawasaki, Kanagawa Prefecture Ward Kamiodanaka 1015, Fujitsu Limited (56) Reference JP 63-198349 (JP, A) JP 62-85877 (JP, A) JP 60-143787 (JP, A)

Claims (1)

[Claims] 1. A single operational amplifier mounted on an integrated circuit chip having a built-in logic circuit part, and a parallel-arranged negative-side analog signal input terminal and analog signal output terminal in the operational amplifier. A semiconductor integrated circuit characterized by comprising a switch which, when closed, makes the operational amplifier a voltage follower configuration, and a control terminal which is drawn out to perform on / off control of the switch. apparatus.