Horology: time measuring systems or devices – Time interval – Electrical or electromechanical
Reexamination Certificate
1998-06-22
2001-03-06
Miska, Vit (Department: 2859)
Horology: time measuring systems or devices
Time interval
Electrical or electromechanical
C324S073100, C714S736000, C714S738000
Reexamination Certificate
active
06198699
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an IC (Integrated Circuit) testing apparatus which is used to measure the execution time of self a function which is executed automatically and independently by IC chip to be tested.
This application is based on patent application No. Hei 09-172502 filed in Japan, the content of which is incorporated herein by reference.
2. Description of Related Art
A memory IC with an automatic function is increasing in popularity, in particular, flash memory ICs with an automatic program function or an automatic erase function. These automatic functions generally take a long time to execute, (as long as 30 seconds, for example), and the execution time for each IC is different.
The test for the automatic function mentioned above also takes a long time and, at the same time, increases the cost for the test. Also, the user sometimes must select the ICs depending on the execution time of the automatic function, in order to avoid the long testing time.
There is a problem in that the conventional IC testing apparatus cannot measure the execution time of the automatic function, even though some testing apparatuses can stop the test halfway when all the DUTS (Device Under Test) which are simultaneously tested have passed the test before the predefined maximum testing time. The stop halfway is possible because of providing an evaluation circuit for the automatic function with minimum execution time, which has a different time for each DUT.
Device selection based on the execution time of the automatic function requires a very long time to calculate the time to the transition point using a judging result for every cycle which is stored in the memory. A conventional IC testing apparatus cannot make an automatic device selection based on the execution time of an automatic function because a circuit which measures the execution time of an automatic function of the DUT is not provided.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an IC testing apparatus which is capable of measuring an execution time of an automatic function for each DUT by a one-time test, and to make a grading of each DUT based on above measurement.
In order to attain this object, the present invention provides an IC testing apparatus for a burn-in check comprising an evaluation circuit of the automatic function with minimum execution time; a timer activated by the evaluation circuit of the automatic function with minimum execution time; a timer counter activated by the timer, and stopped by each result of the IC to be tested; and is further capable of measuring the execution time of the automatic function of each IC to be tested.
The present invention further provides an IC testing apparatus according to the above, which is further capable of selecting an IC by the execution time of the automatic function of each IC with minimum selection time, wherein each of said evaluating results of the IC to be tested is sent to the timer counter via an output pin selector for the automatic function, and said timer counter is used for automatic measuring of the execution time of an automatic function of each IC by being realized with a minimum circuit.
With the IC testing apparatus of the present invention, the execution time of the automatic function for each DUT can be measured by a one-time test, and automatic grading of the DUT is also possible based on the measured execution time of the automatic function.
REFERENCES:
patent: 4646299 (1987-02-01), Schinabeck et al.
patent: 5696772 (1997-12-01), Lesmeister
Ando Electric Co. Ltd.
Fish & Richardson P.C.
Miska Vit
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