JPS6150076A - Semiconductor integrated circuit device - Google Patents

Abstract

PURPOSE:To enable the measurement of characteristics of a circuit to be measured within an IC without putting a gold wire thereon, by controlling an analog switch connected to an input/output terminal of an analog circuit section from outside. CONSTITUTION:When measuring characteristics of bandpass filters 111-114 for spectral analysis of an input signal IN by the frequency band, linear elements S1, S3, S3 and S4 are set for conducting state and other linear elements for high output impedance state by a control signal CS and a test signal is inputted from an input terminal 14 to obtain outputs an external terminals 151-154. On the other hand, when measuring rectifier circuits 122 and 124, linear elements S2, S7, S5 and S8 are set for conducting state and a test signal is supplied from external terminals 151 and 153 to obtain outputs at external terminals 152 and 154. When measuring a lowpass filter 134, linear elements S8 and S9 are set for conducting state and a test signal is supplied from the external terminal 154 to obtain the output thereof at the external terminal 153.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a semiconductor integrated circuit device configured so that each circuit inside an IC can be inspected from the outside.
It is particularly suitable for testing operating characteristics in analog circuits.

[Technical background of the invention and its problems]

Conventionally, when testing a part of the circuit inside an IC, there are two people involved in the circuit under test: 1. By magnifying the output part with a microscope and applying an ultra-thin gold wire, the signal is extracted to the outside of the IC.

When evaluating such ICs, a device called a manipulator is used to apply the gold wire, but with recent advances in microfabrication technology, it has become difficult to apply the gold wire. .

In addition, since a large device called a manipulator is used, the measurement equipment is also large, making testing difficult because, for example, when trying to measure temperature characteristics or reliability, it cannot be placed in a constant temperature bath. .

Furthermore, since it is necessary to expose the IC chip in order to apply the gold wire, it is not only impossible to see the characteristics of the IC chip when it is sealed in a package, but also the characteristics may change due to light entering. Yes, there were many problems.

Furthermore, since it is impossible to apply gold wire during mass production, there are many problems such as IC testing, which becomes a bottleneck during mass production.

[Purpose of the invention]

This invention was made in view of the above circumstances,
The purpose is to provide a semiconductor integrated circuit device that can measure the characteristics of a circuit under test inside an IC without applying a gold wire.

[Summary of the invention]

That is, in this invention, in order to achieve the above object, an IC is connected to the input terminal and output terminal of the analog circuit section to be inspected via an analog switch (or amplifier).
Connect the input and output lines that are led out to the outside of the IC, and supply the analog switch with a control signal from outside the IC to control the analog switch to be in a conductive state during testing and in a cutoff state during normal operation (in the case of an amplifier) is set to amplification operation during testing, and set to high impedance state during normal operation)
During testing, a test signal or drive signal is supplied from the outside to the input line, and the output of the circuit under test is taken out from the output line, thereby controlling the operation of the analog circuit inside the IC. Characteristics can be easily measured under the same conditions as in actual use.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a basic tract analyzer as an example. In FIG. 1, 111-114 are band-pass filters, and these band-pass filters 11. ~
114 have different center frequencies and bandwidths, as shown in FIG. 121 to 124 are rectifier circuits, and the rectifier circuits 121 and 122, and 123 and 124 have the same configuration. Further, 131 to 134 are low-pass filters, and the low-pass filters 131 and 132, 133, and 134 have the same configuration, respectively.

In the above configuration, the input signal IN supplied to the input terminal 14 is passed through the bandpass filter 11 . ~114, and is spectrally decomposed into corresponding frequency bands by these bandpass filters 111~114. Then, the energy in each band is extracted by rectifier circuits 121 to 124 and Ronos filters 131 to 134, and the output signal OUT, ~0
Obtained as UT4.

Such a spectrum analyzer includes four types of bandpass filters, two types of rectifier circuits, and one type of Rono J.
? It is necessary to evaluate the characteristics of filters.

For this reason, in FIG. 1, a linear element s, -8, is provided. These linear elements 81 to S are, for example, analog switches or linear amplifiers, and are operated as linear elements or set to a high output impedance state by the control signal C8. And these linear elements 81
- Bandpass filter 11 as a circuit under test using S9. ~114, the output section of the am circuits 122, 124 and the low-pass filter 134 are connected to the external terminals 151~
It is selectively connected to signal lines (lines) 161 to 164 connected to signal line 154. Note that the bandpass filter 112*
114 and rectifier circuit 122 r 124 can each be set to a high output impedance state or a state close to it by control signal CS.

In the above configuration, the pantone 4 filter 11
When measuring the characteristics of 1 to 114, the linear element Sl
r S3r S4 and S6 are respectively rendered conductive by the control signal C3, and the other linear elements 82 . S5 and S7~
S9 is each set to a high output impedance state.

When a test signal is inputted from the input terminal 14, the outputs of the bandpass filters 111 to 114 are obtained from the external terminals 15 and 154, respectively.

On the other hand, when measuring the S rectifier circuit 12z+124, the linear elements s21, S71 s, and S8 are made conductive by the control signal CS, and the other linear elements S1
*Ss + S4 r S6 and S9 are each set to a high output impedance state. A test signal is supplied to the rectifier circuit 122 from the external terminal 151 via the line 161 and the linear element S2, and its output is obtained from the external terminal 152 via the linear element S1 and the line 162, respectively. Further, a test signal is supplied to the rectifier circuit 124 from the external terminal 153 via the line 163 and the linear element S, and its output is obtained from the external terminal 154 via the linear element S8 and the line 164. However, external terminal 1! In order to prevent the test signal input from H, 153 from short-circuiting with the output signals of the band-pass filters 112 and 114, it is necessary to set the output terminals of the band-pass filters 112 and 114 to a high output impedance state using the control signal C8. be.

Furthermore, when measuring the low-pass filter 134, the linear elements s8189 are each set to a conductive state by the control signal C8, and the linear elements S1 to s7 are all set to a high output impedance state. Then, from the external terminal 154, the 2-in-1
64, a low-pass filter 134 via a linear element Sst''
A test signal is supplied to the linear element S9, and its output is obtained from the external terminal 153 via the line 163.

At this time, the output signal of the rectifier circuit 124 is in synch with the test signal.
- The rectifier circuit 124 is controlled by the control signal C8 to prevent
set the output of the output to a high output impedance state.

Therefore, with this configuration, the circuit characteristics inside the IC can be selectively measured using the control signal C8 supplied from outside the IC.

FIG. 3 shows an example of the configuration of the linear elements 81 to S9, in which the control signal C8 and the control signal
8 is inverted by an inverter 17, and the conduction is controlled by supplying the respective signals. Therefore, when the control signal CS is at a high (°゛H”) level, the terminal 11J1r1
82 is conductive, and when it is low (“L”) level, it is cut off (
high output impedance) state.

FIG. 4 shows another example of the configuration of the linear elements 81 to S9, which are girth followers. That is,
The constant current bias CB is an N-channel type MOS whose one end is grounded. These MOS transistors Qs and Q4 are respectively supplied to the darts of Q4.
acts as a constant current source. The above MOS transistor Qs
- Between the dart of Q4 and the ground point, there is an N-channel MO whose conduction is controlled by the inverted signal C3 of the control signal CS.
S transistor Q5 is connected. Above MO8),
At the other end of the 77 resistor Q3, there is an N-channel MOS)
One ends of transistors Qa and Q7 are connected to each other.

The other ends of these MOS transistors Qs and Q7 are respectively connected to a power supply terminal 19 to which a power supply voltage vDD is applied via P-channel type MOS transistors Qs and Q9 forming a current mirror circuit. A P-channel MOS transistor QIO whose conduction is controlled by a control signal CS is connected in parallel to the MO8 transistor Q9. Further, a dirt is connected to the other end of the MOS transistor Q4 by the MO8 transistor Q g + Q
A power supply terminal 19 is connected through a P-channel type MOS transistor Qo connected to the connection point between to and Q7.

A capacitor C is connected between the connection point between MO3) transistors Q4 and Qll and the connection point between MO8) transistors Qs + Qto and Q7. And the above M
The output terminal 182 and the dart of the MO3) transistor Q6 are connected to the connection point between the transistors Q4 and Qtt. In addition, the above MQS) Ran Zosta Q
An input terminal 181 is connected to the dart of 7, and this input terminal 18. The output terminal of the circuit under test is connected to.

In the above configuration, the control signal C8 is at "H" level (C8 is at "L" level), MOS transistor Q5 is off, Q31Q4 is on, and Qlo is off, so that there is no signal from the circuit under test. The signal supplied to the input terminal 181 is linearly amplified and output from the output terminal 182. On the other hand, when the control signal C8 reaches the ItL7 level, the MOS transistor Q5 is turned on, so the MO
S transistor Q3. Q4 is turned off. Also, M
By turning on the OS transistor Qto,
The dirt potential of the MOS) transistor Qtt rises and the MOS) transistor Qtt turns off. Therefore, no amplification operation is performed, and the output terminal 18□ is in a high output impedance state.

By using the linear element described above, it is possible to control the output terminal of the circuit under test according to the control signal supplied from the outside.
Since it can be selectively connected to the external terminal of C in a linear relationship, there is no need to apply a gold wire or the like, and desired circuit characteristics can be measured even when it is sealed in an ICf package. This enables automatic measurement using a tester during mass production of ICs.

Note that in the above embodiment, lines 161 to 164 were treated as unrelated to the original functions of the IC, but since the output of the circuit under test is not input to these lines except during testing, For example, a digital bus line or the like may be shared. [Effects of the Invention] As explained above, according to the present invention, it is possible to measure the characteristics of a circuit under test inside an IC without applying a gold wire. A semiconductor integrated circuit device that can be measured is obtained.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram for explaining a semiconductor integrated circuit device according to an embodiment of the present invention, FIG. 2 is a characteristic diagram for explaining the characteristics of the bandpass filter in FIG. 1,
FIGS. 3 and 4 are circuit diagrams for explaining an example of the configuration of the linear element shown in FIG. 1, respectively. 14...Input terminal, 151-154...External terminal,
161-164...Signal line, 5l-89...Linear element, CS...Control signal. Applicant's agent Patent attorney Takehiko Suzue Figure 1

Claims (4)

[Claims] (1) Linear elements connected between multiple analog circuits under test formed in one chip and signal lines connected to the input and output ends of these analog circuits under test and external terminals, respectively. and a control means for selectively controlling these linear elements to connect the input end and the output end of a predetermined analog circuit under test to the signal line in a linear relationship,
A semiconductor integrated circuit device characterized in that it is configured to supply a test signal from the outside to the analog circuit under test selected by the control means and obtain its output from an external terminal. (2) The semiconductor integrated circuit device according to claim 1, wherein the linear element comprises a transmission gate that is controlled to be turned on/off by a control signal. (3) The semiconductor integrated circuit device according to claim 1, wherein the linear element comprises a voltage follower that is controlled by a control signal and amplifies the output signal of the analog circuit under test. (4) The semiconductor integrated circuit device according to claim 1, wherein a bus line is shared as the signal line.