| 摘要 |
PURPOSE:To test it in a short period of time whether a severe reference is satisfied or not by making changeable a resistance value between one of two power sources and a memory cell based on an external input signal. CONSTITUTION:In the case of normal use, a test signal T is made H. At such a time, a resistance component is formed by the ON resistance of a transistor TrT2 and since the ON resistance is at a certain level to be ignored, however, no adverse influence is generated in the operation of the memory cell in the case of normal use. On the other hand, when inspecting the forwarding of an SRAM, the test signal T is turned to be L and a simple function test is executed. The test is executed for inspecting whether a threshold voltage is made abnormal at one part of an internal TR or not, and the characteristic of the abnormal memory cell is further made adverse by the resistance component to be formed between the memory cell and a ground level in the case of normal use. Then, by suitably setting the ON resistance of the TrT1 large, the characteristic can be made adverse to the level not to present an FF function. Thus, the defect of the memory cell loosing the FF function can be detected by the simple function test. |
