JPH05346456A - Circuit and method for monitoring address signal - Google Patents

Abstract

PURPOSE:To provide a simple circuit for checking that an address signal supplied from a driver board is inputted correctly to a dynamic IC burn-in board. CONSTITUTION:Address signals inputted to a burn-in board 2 are synthesized through the intermediary of resistors respectively and a synthesized output thus obtained is inputted to a comparator 3 and compared with a reference signal A inputted to the comparator 3. Accordingly, the number of pins of a socket for connecting a driver board with the burn-in board can be lessened and, in addition, comparators for checking up the address signals can be reduced to one.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to monitoring of an address signal of a dynamic burn-in device used for burn-in test of an IC, and an address signal supplied from a driver board is accurately input to the burn-in board. Whether or not it can be confirmed by a simple method and circuit.

[0002]

2. Description of the Related Art Burn-in equipment is an equipment used for burn-in processing of ICs. The burn-in test is widely performed to ensure the quality control of manufactured ICs.

An IC produced in a factory is heated to room temperature to 200 ° C. by a dynamic burn-in device, and in this state, an address signal is given to each IC to set the same environment as the actual operating state, and this is done for a long time. Maintain a good state. This is the burn-in process, and after this I
C is compared with the input / output of various test patterns by a burn-in tester to judge whether it is good or bad, and perform screening without judgment.

By the way, in order to confirm whether or not the address signal is accurately input to each burn-in board,
As shown in FIG. 2, the address signal input to the burn-in board is re-input to the driver board, and the comparator compares the returned signal as soon as it is accurate.

That is, the signals are re-input for each signal to the driver board for comparison, but since 28 driver's address signals are input to the burn-in board from one driver board. , The number of pins on the socket is required not only for input to the burn-in board but also for confirmation.

[0006]

Since the number of required pins is increased, a large socket is required, and one comparator is required for one signal. Therefore, if there are 28 signals, 28 comparators are also required. Becomes

If the number of pins can be reduced, the socket can be downsized or the pins can be used for other purposes, which is convenient. If the number of signals to be compared can be reduced, the number of comparators can be reduced, and the driver board can be simplified.

[0008]

Therefore, the address signal monitoring circuit according to the present invention synthesizes the address signals input to the burn-in board via resistors, inputs the synthesized output to the comparator, and inputs the synthesized output to the comparator. The reference signal is compared with the reference signal.

In the address signal monitoring method, a plurality of address signals whose wavelengths are sequentially doubled are input to the burn-in board, the plurality of address signals are input to the burn-in board, and then the plurality of address signals are combined. It is intended to be compared with.

[0010]

Next, the address signal monitoring method will be described. A from driver board to burn-in board
It is assumed that five kinds of address signals ₀ , A ₁ , A ₂ , A ₃ , and A ₄ are input. As shown in FIG. 3, the address signal has a wavelength of A _{1 that} is twice that of A ₀ , and A ₂ is 2 times the wavelength of A ₁ .
Times, sequentially A ₃ is twice the A _2, sequential A ₄ is set to be twice the wavelength of A _3.

That is, A _{m + 1} has a wavelength that is twice as large as A _m . This is the same even if there are more address signals.

When the address signals A ₀ , A ₁ , A ₂ , A ₃ , and A ₄ thus input are combined, a waveform like A _n is obtained. It suffices to compare with a comparator whether this has the same waveform as the reference waveform A.

The synthesized waveform has a waveform like A _{n. When} the synthesized waveform A _n is decomposed, it becomes like A _x shown in FIG.

That is, when the signal of A _x is decomposed into units of the same length as the signal of A ₀ , A ₀ , A ₁ , A ₂ , A
_It can be seen that only a signal of ₃ or A ₄ increases the portion where A _x exists.

For example, the portion where the signal of A _x first becomes high is due to A ₀ , and the next portion is due to A ₁ . And it can be seen that the next part is due to A _{2 in} one. Thus, there is a portion where the composite signal A _n is high due to any one of the address signals.

If any of the address signals is short-circuited and is not accurately input to the burn-in board, the waveform of the combined signal is different from that of the reference signal A.

For example, as shown in FIG. 5, the address signal A
_{If 3} is shorted, the combined signal is the reference signal A
Different from A _y, the composite signal that should originally be high becomes low only in that part due to the signal of A ₃ . From this, it can be seen that the address signal is not accurately input to the burn-in board.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of an address signal monitoring circuit according to the present invention will be described with reference to FIG.
Is a driver board, and 2 is a burn-in board. Address signals A ₀ , A ₁ , A ₂ , A ₃ , and A ₄ are input from the driver board 1 to the burn-in board 2. In the illustrated example, five kinds of address signals are used for convenience of explanation, but the number of address signals is not limited to this number.

The address signal input to the burn-in board is combined via the resistor R. And this composite signal A
Input _n to the comparator 3. Meanwhile, the reference signal transmitter 4
Then, the reference signal A is input to the comparator 3. And
The comparison results of the comparator 3 are sequentially output.

As described above, if the address signals A ₀ , A ₁ , A ₂ , A ₃ and A ₄ are input to the burn-in board 2 so that the wavelengths are sequentially doubled, the composite signal A _n
By comparing the reference signal A with the comparator 3,
As soon as the address signal is correctly input to the burn-in board 2, it can be confirmed at any time.

[0021]

As described above, according to the address signal monitoring circuit and the address signal monitoring method of the present invention, the wavelengths are sequentially set to 2 on the burn-in board.
The multiple address signals that are doubled are input, and after input to the burn-in board, the multiple address signals are combined and compared with the reference signal, so this composite is performed from the burn-in board to the driver board. Since only the signal needs to be fed back and compared with the reference signal, the number of socket pins connecting the driver board and the burn-in board can be reduced, and moreover, only one comparator for checking the address signal can be used. it can.

[Brief description of drawings]

FIG. 1 is a monitoring circuit of the present invention.

FIG. 2 is a conventional monitoring circuit.

FIG. 3 is an explanatory diagram showing a method of monitoring an address signal.

FIG. 4 is an explanatory diagram showing a method of monitoring an address signal.

FIG. 5 is an explanatory diagram showing a method of monitoring an address signal.

[Explanation of symbols]

1 Driver board 2 Burn-in board 3 Comparator 4 Reference signal transmitter A ₀ Address signal A ₁ Address signal A ₂ Address signal A ₃ Address signal A ₄ Address signal _An Synthetic signal A _x Synthetic signal A _y Synthetic signal A Reference signal

Claims (2)

[Claims] 1. A burn-in board is provided with a plurality of address signals whose wavelengths are sequentially doubled. After being input to the burn-in board, the plurality of address signals are combined and compared with a reference signal. An address signal monitoring method characterized by the above. 2. An address characterized in that the address signals input to the burn-in board are combined through resistors, and the combined output is input to a comparator and compared with a reference signal input to the comparator. Signal monitoring circuit.