JPS63181457A - Semiconductor integrated circuit device - Google Patents

Abstract

PURPOSE:To enhance the control accuracy of an end product by a method wherein the potential at an internal circuit is measured at one pad for test use by operating a switch built in an IC chip so that the size of the chip can be made small. CONSTITUTION:Individual output terminals of analog switches 3a-3n, whose input terminals are connected to a comparison-reference voltage at individual comparators 2a-2n, are connected to one pad 7. In addition, an analog-switch control circuit 4 to control the switching-on and switching-off operation of these switches is installed. If a clock is input to a clock-input terminal 11, one out of analog switches is turned on in accordance with the number of the clock. Accordingly, if the individual analog switches 3a-3n are switched by the analog-switch control circuit 4, the comparator circuits 2a-2n can be controlled by means of one pad 7 for test use and the number of pads can be reduced. In addition, this pad can be used for the measurement of a voltage inside an IC chip.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor integrated circuit device, and particularly to a circuit configuration for accurately managing the semiconductor integrated circuit device.

[Conventional technology]

FIG. 3 shows an example of a conventional semiconductor integrated circuit device, in which 1 is an IC chip, 2a to 2n are comparators,
3a' to 3n' are external selector switches, 5 is a constant current source, 6
a to 6n are resistors for setting comparison reference voltages of the comparators 2a to 2n, respectively; 7 is a test pad for measuring the comparison reference voltage; 8 is a measurement pin; 9 is a voltmeter;
0 indicates a voltage source.

Next, the operation will be explained.

In FIG. 3, when measuring the comparison reference voltage of each of the comparators 2a to 2n, the switches 3a' to 3n/ are sequentially switched and the voltmeter 9 measures the potential. In addition, when checking the offset and switching function of each comparator 2a to 2n, input the voltage from the voltage source 10, and compare the input voltage at which the output of the comparator is inverted with the value of the voltmeter 9 measured earlier. Manage.

[Problem that the invention seeks to solve]

Conventional semiconductor integrated circuit devices are configured as described above, so it is necessary to take out a pad for each comparison reference voltage, and the need to provide multiple pads increases the chip area. Since it is difficult to extract all the pads, including those not used for the final product, to the pins of the final product, there has been a problem in that the control accuracy of the final product is reduced.

This invention was made to solve the above problems, and provides a semiconductor integrated circuit device that can reduce the number of pads, reduce the chip area, and improve the precision of controlling the shape of the final product. The purpose is to obtain.

[Means for solving problems]

A semiconductor integrated circuit device according to the present invention includes a plurality of switches each having an input terminal connected to each internal circuit and an output terminal connected to one test pad;
A circuit for controlling OFF is built into the IC chip.

[Effect]

In this invention, the potential of each internal circuit can be measured with a single test pad by switching the switches built into the IC chip, so the number of pads can be reduced and the chip area can be reduced. Since the number of pads taken out in the final product can be reduced, the control accuracy in the final product can be improved.

〔Example〕

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

FIG. 1 is a configuration diagram showing a semiconductor integrated circuit device according to an embodiment of the present invention, and FIG. 2 is a time chart showing switching of analog switches built in this integrated circuit.
In the figure, 1 is an IC chip, 2a to 2n are comparators, 7 is a pad, and 3a to 3n are each comparators 2a to 2.
These are analog switches whose input terminals are connected to n comparison reference voltages, and each output terminal of these switches is connected to one pad 7. 4 is each analog switch 3a~
3n is an analog switch control circuit that controls ON/OFF, 5 is a constant current source, 6a to 6n are resistors that create comparison reference voltages for each comparator, 8 is a measurement pin, 9 is a voltmeter, 10 is a voltage source, 11 is a clock input terminal.

Next, the operation will be explained.

As shown in FIG. 2, when a clock is input to the clock input terminal 11, one of the analog switches corresponding to the number of clocks is turned on. Therefore, by inputting a clock corresponding to a point to be measured, the analog switch connected to that point is turned on, and the potential output to the pad 7 can be measured by the voltmeter 9. Also, when managing comparator offsets and functions, the voltage source 10
Management can be performed by comparing the voltage inputted with the value measured by the voltmeter 9 by turning on the analog switch corresponding to the inverted comparator.

In this way, in this embodiment, the comparators 2a to 2n can be managed by one test pad 7 by switching the analog switches 3a to 3n using the analog switch control circuit 4, so the number of pads can be reduced. By eliminating this, the chip area can be reduced, and the number of pads taken out in the final product can be reduced.
It is possible to improve the control accuracy of the final product.

In the above embodiment, the case related to the measurement of the comparator section and its reference voltage was shown, but the present invention can also be used to simply measure the voltage inside an IC chip, and the same effects as in the above embodiment can be obtained.

〔Effect of the invention〕

As described above, according to the semiconductor integrated circuit device of the present invention, the input terminals are connected to each internal circuit, and the output terminals are connected to one
Since a plurality of switches connected to each test pad and a circuit for controlling on/off of each switch are built into the IC chip, it is possible to reduce the number of pads and reduce the chip size. This has the effect of improving the control accuracy of the final product.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a semiconductor integrated circuit device according to an embodiment of the present invention, FIG. 2 is a diagram showing a time chart of analog switch switching in this embodiment, and FIG. 3 is an example of a conventional semiconductor integrated circuit device. FIG. In the figure, 1 is an IC chip, 23 to 2n are comparators, 3a to 3n are analog switches, 4 is an analog switch control circuit, 5 is a constant current source, 63 to 6n are resistors, 7 is a pad, and 8 is for measurement. Pin, 9 is voltmeter, 10
is a voltage source, and 11 is a clock input terminal. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (3)

[Claims] (1) A plurality of internal circuits, one test pad for measuring each potential of the internal circuits, an output terminal connected to the one test pad, and an input terminal connected to the plurality of test pads. A semiconductor integrated circuit device comprising a plurality of switches connected to each of the internal circuits, and a control circuit for controlling on/off of each of the plurality of switches built into an IC chip. . (2) The semiconductor integrated circuit device according to claim 1, wherein the switch is an analog switch. (3) The semiconductor integrated circuit device according to claim 1 or 2, wherein the internal circuit is a comparator.