JPH0572259A - Measuring method for semiconductor integrated circuit device - Google Patents

Abstract

PURPOSE:To measure a base current of an inputs stage transistor accurately. CONSTITUTION:A constant voltage source 6 is set to a rating value of a semiconductor integrated circuit device 1 to be measured. A relay 11 is turned OFF and a voltage V1 divided with resistors 13 and 14 from a constant voltage source 12 is measured with a voltmeter 15. Then, the relay 11 is turned ON and a voltage V2 divided with the resistors 13 and 14 from the constant voltage source 12 is measured with the voltmeter 15 with a transistor 4 at an input stage of the semiconductor integrated circuit device 1 being enabled. With the relay 11 ON, a base current flows through the transistor 4 and a voltage drop portion is developed as difference of measured values. Thus, the base current IB can be determined by the following formula (wherein R14 represents a resistance value of the resistor 14): IB=V1-V2/R14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of measuring a semiconductor integrated circuit device.

[0002]

2. Description of the Related Art A conventional method for measuring the base current of an input-stage transistor in a semiconductor integrated circuit device in which the base of the input-stage transistor is directly connected to a terminal will be described with reference to the circuit diagram of FIG. explain.

An input stage transistor 4 in which an internal circuit 5 of a semiconductor integrated circuit device 1 to be measured is connected to an emitter
In addition, the base is directly connected to the input terminal 3. An externally applied constant voltage source 8 is connected to the input terminal 3 of the base through an ammeter 7. A power supply 6 is connected to the power supply terminal 2. In addition, 9 is a ground line.

A voltage V _CC determined by the rating of the semiconductor integrated circuit device 1 is applied to the power supply terminal 2 from an externally applied constant voltage source 6, and an input stage transistor 4 is applied to the input terminal 3 by an externally applied constant voltage source 8. Apply sufficient voltage to activate. At this time, the ammeter 7 measures the base current of the input stage transistor 4.

[0005]

In such a measuring method, the measurement error (offset) of the ammeter 7 has a significant influence. Particularly, when the value of the current amplification factor h _FE is large, the base current becomes a very small value, and the measurement error of the ammeter becomes so large that it cannot be ignored.

The present invention solves the above-mentioned conventional problem, and considers that an ammeter error of an externally applied constant voltage source has an influence on the measurement of the base current, and by reducing the error, the base current can be accurately measured. It is intended to provide a method that can be well measured.

[0007]

SUMMARY OF THE INVENTION A method of measuring a semiconductor integrated circuit device according to the present invention comprises: a first constant voltage source connected in series;
Connect the base of the transistor to be measured to the connection point of the resistor of 2 through the switching device, connect the voltmeter, measure the voltage when the switching device is turned off, and then turn it on. The voltage is measured when

[0008]

In this method, the switching device is switched, the voltage is measured by the voltmeter in the same measurement range, and the voltage difference is examined, whereby the offset error of the measuring device can be made almost zero.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 is a circuit diagram for connecting the base of an input stage transistor of a semiconductor integrated circuit device to a terminal and measuring the base current of the input stage transistor.

The base of the input stage transistor 4 of the semiconductor integrated circuit device 1 is directly connected to the terminal 3. Further, the emitter of the input stage transistor 4 is connected to the internal circuit 5. Further, the collector of the input stage transistor 4 is connected to the power supply terminal 2.

The externally applied constant voltage source 12 is provided with resistors 13 and 14
Are connected in series, and the other end of the resistor 14 is connected to the ground line. The connection point of the resistors 13 and 14 is connected to the input terminal 3 of the base of the input stage transistor 4 via the relay 11 as a switching device. Further, a voltmeter 1 is provided between the connection point and the ground line 9.
5 is connected.

In the circuit having such a configuration, a voltage having a value determined by the rating of the semiconductor integrated circuit device 1 is applied to the power supply terminal 2 from the externally applied constant voltage source 6. In this state, the relay 11 is turned off (non-conductive), and the voltage divided by the resistors 13 and 14 from the externally applied constant voltage source 12 is applied to the voltmeter 1.
Measure at 5. The voltage at this time is V ₁ .

Next, the relay 11 is turned on (conducted),
The voltage divided by the resistors 13 and 14 is measured by the voltmeter 15 in the same measurement range as when the voltage V ₁ is measured. The voltage at this time is V ₂ .

The resistor 1 is turned on by turning on the relay 11.
The voltage generated by the resistance division of 3 and 14 is applied to the base terminal 3 of the input stage transistor 4. As a result,
The input stage transistor 4 becomes active, and a voltage is generated across the resistor 14 by subtracting the voltage drop corresponding to the current flowing through the base terminal 3 from the voltage generated when the relay 11 is off.

Therefore, the base current I _B of the transistor 4 can be obtained from the following equation.

I _B = V ₁ −V ₂ / R ₁₄ where R ₁₄ is the resistance value of the resistor 14.

As described above, in the present embodiment, by switching the relay 11 and using the voltmeter 15 to check the measured voltage difference in the same measurement range, the offset error of the measuring instrument can be made almost zero. As a result, the measurement error is reduced, and the base current of the transistor 4 can be accurately measured even when the current amplification factor h _FE of the transistor is high.

[0019]

According to the method of the present invention, a resistor for voltage division is connected to a constant voltage source, and the divided voltage is supplied to the base of a transistor to be measured through a switching device, and switching is performed. Since the voltmeter measures the supply voltage to the base when the device is off and when it is on, the offset error of the measuring device can be eliminated by checking the difference in the measured voltages in the same measurement range. As a result, the measurement error is reduced, and the base current can be accurately measured even when the current amplification factor h _FE of the transistor is high.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a measuring method of a semiconductor integrated circuit device according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a conventional measurement method.

[Explanation of symbols]

 1 semiconductor integrated circuit device 2 power supply terminal 3 input terminal 4 input stage transistor 5 internal circuit 6, 12 constant voltage source 9 ground line 11 relay 13, 14 resistor 15 voltmeter

Claims (2)

[Claims] 1. A base is connected via a switching device to a connection point of a constant voltage source, first and second resistors connected in series to the constant voltage source, and the first and second resistors. A transistor and a voltmeter whose one end is connected to the connection point of the first and second resistors, the voltage when the switching device is turned off is measured, and then when the switching device is turned on. Measuring the voltage of the semiconductor integrated circuit device. 2. A method for measuring a semiconductor integrated circuit device according to claim 1, wherein the switching device is turned off and turned on and the voltage at each time is measured by a voltmeter in the same measurement range.