JPH01120125A - Method for testing a/d converting function - Google Patents

Abstract

PURPOSE:To enable A/D conversion without waiting for decision making and to shorten a test time storing a RAM temporarily with data which is A/D- converted by a device to be measured and then using the data for decision making by a testing device. CONSTITUTION:The A/D conversion part 5 of the device(DUT) 3 to be tested performs all of A/D conversion in response to a digital signal do for testing outputted in order from a tester 1. Then when the obtained digital signal 8d) is stored in the RAM 8, the signal d0 and a control signal C are inputted from the tester 1 to the RAM 8 and the signal (d) stored in the RAM 8 are read out in order thereafter and sent to the tester 1. When some signal d0 for testing is supplied as an address input, the tester 1 reads a corresponding signal (d) out of the RAM 8 and a CPU 7 compares those signals (d) and d0 with each other to decide whether or not the A/D converting function of the conversion part 5 is normal from the comparison result. This test is conducted at a time.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an A/D converter of a semiconductor device having an A/D converter.
The present invention relates to a method for testing conversion functions, and in particular to reducing the testing time.

[Conventional technology]

FIG. 2 is a block diagram of a test system using a conventional A/D conversion function test method. In the figure, 1 is a semiconductor integrated circuit test equipment (hereinafter referred to as a tester), and 2 is a tester 1.
Test digital signal d output from A D/A converter 3 converts the signal into an analog signal a, and 3 is a device under test (hereinafter referred to as OUT). This DUT 3 has a central processing unit (hereinafter referred to as CPU) 4, an A/D conversion section 5 and an output section 6 controlled by this CPU 4.
·are doing. 7 is a CPLI of the tester 1, which outputs a digital signal d from the output section 6 of the DLJT 3 and a digital signal d for testing. Compare with DU
It is configured to determine whether the function of the A/D converter 5 of T3 is good or bad.

Test operations in such a test system are performed as follows. First, a test digital signal d is sent from the tester 1. is output. This digital signal d.

is converted into an analog signal a by the D/A converter 2, and D
Given to UT3.

In the DUT 3, the applied analog signal a is converted into a digital signal d by the A/D converter 5, and outputted from the output unit 6. This digital signal d is input to the tester 1,
In the tester 1, the test digital signal d sent out earlier. The CPU 7 compares the digital signal d sent from the DUT 3 with the A/D converter 5 of the DUT 3.
The quality of the A/D conversion function is determined. When the determination is completed, the tester 1 outputs a new test digital signal d0, and the same test as above is repeated.

[Problem that the invention seeks to solve]

Since the conventional A/D conversion function test method is performed as described above, the next data is not input to the DUT 3 until the tester 1 finishes determining one data. Therefore, there is a problem in that it takes a long time to complete the determination on all data.

The present invention has been made to solve these problems, and an object of the present invention is to provide an A/D conversion function test method that can shorten test time.

(Means for Solving the Problems) The A/D conversion function test method according to the present invention temporarily stores data A/D converted by the device under test in response to a test signal in a RAM, After A/D conversion is completed for all test signals, the data stored in the RAM is sequentially sent to the test equipment to test the A/D conversion function of the device under test. be.

(Function) In this invention, the data A/D converted by the device under test is once stored in the RAM and then subjected to judgment by the test equipment. A/D conversion can be performed.

(Embodiment) FIG. 1 is a block diagram of a test system showing an embodiment of the A/D conversion function testing method according to the present invention. In the figure, numerals 1 to 7 are the same as the test system of the conventional method described above. 8 is a RAM for temporarily storing the digital signal d output from the output section 6 of the DUT 3;
0 is shared for address input of this RAM. Further, the RAM 8 is controlled by a control signal C output from the tester 1.

Test operations in such a test system are performed as follows. First, the tester 1 outputs a test digital signal d0. This digital signal d.

is converted into an analog signal a by the D/A converter 2, and D
Given to UT3.

In the DUT 3 , the analog signal @a is converted into a digital signal d by the A/D converter 5 and outputted from the output unit 6 . This digital signal d is sent to RAM8. At the same time, a test digital signal d0 to be used as an address signal and a control signal C to control the filling are inputted from the tester 1 to the RAM 8.

Then, the RAM 8 is
Specify the address of DUchohs at the corresponding address.
The digital signals d are stored. This series of actions
This is repeated for all test digital signals d0.

Then, in response to the test digital signal d0 sequentially output from the tester 1, all A/D conversions are performed using the DLJT.
When all the converted digital signals d are stored in the RAM 8, the tester 1
Then, a test digital signal d as an address signal is sent to the RAM 8.

Then, a control signal C for controlling readout is input, and thereafter, data at each address, that is, each stored digital signal d, is sequentially read out from the RAM 8, and the tester 1
sent to. When a certain test digital signal d0 is given as an address input, the corresponding digital signal d is read out from the RAM 8, and the tester 1
Now let's look at the read digital signal d and the test digital signal d given to RAM8 as an address signal.
0 by the CPU 7, and from the comparison result DU
The quality of the A/D conversion function of the A/D conversion unit 5 of T3 is determined.

In other words, in this A/D conversion function test method, tester 1 outputs all test data, and DUT 3's A
A/D converter 5 converts all these data into A/D converter 5.
By performing conversion, temporarily storing all of the converted data in RAM 8, then sequentially reading out the converted data stored in RAM 8, and comparing the read converted data with the corresponding test data using tester 1. A/D
This is to determine the conversion function.

In the above embodiment, the RAM is used as a means for temporarily storing the data converted by the A/D converter 5 of the DtJ-3.
Although the case is shown in which a memory device is used, other memory devices such as an EEPROM in which data can be electrically written and erased may also be used.

〔Effect of the invention〕

As explained above, according to the present invention, all the data A/D converted by the device under test is temporarily stored in the RAM, and then the data stored in the RAM is judged all at once by the tester. This has the effect of significantly shortening test time.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a test system showing an embodiment of the A/D conversion function test method according to the present invention, and FIG. 2 is a block diagram of a test system showing a conventional A/D conversion function test method. In the figure, 1 is the tester, 3 is the device under test, and 5 is A
8 is a RAM, do is a test digital signal, and d is an A/D converted digital signal. Note that the same reference numerals in each figure indicate the same or corresponding parts. Agent Masuo Oiwa 5: A/D control department dO: Digital signal for testing d: A/DI item also included in the 9I Shintoku figure 2 procedural amendment (voluntary) 1. Incident Display of patent application No. 62-277968 2
, Name of the invention A/D conversion function test method 3, Relationship with the amended person case Patent applicant address 2-2-3 Marunouchi, Chiyoda-ku, Tokyo Name (601) Mamoru Shiki, representative of Mitsubishi Electric Corporation Ya 4, Agent 5, Subject of amendment Akira l1la [Detailed description of the invention column] 6 Contents of amendment (1) Akira Store the data temporarily]. that's all

Claims (1)

[Claims] (1) A/D in the device under test in response to the test signal
The converted data is sequentially stored in RAM, and after A/D conversion has been completed for all the test signals, the data stored in the RAM is sequentially sent to the test equipment to test the device under test. An A/D conversion function test method, characterized by testing an A/D conversion function.