| 摘要 |
An integrated circuit package having external pins includes a function circuit, such as an address buffer, receiving an input voltage through one of the pins. If the input voltage exceeds a maximum rated voltage, the function circuit can be damaged by voltage over-stress. To provide a definitive indication that the function circuit may have been over-stressed, a diode and a fuse are connected in series between the function circuit's pin and ground. When the input voltage nears the maximum rated voltage, the diode biases and applies a voltage to the fuise. The fuse is selected so that when the input voltage exceeds the maximum rated voltage, the applied voltage blows the fuse. At a later time, the function circuit can be tested for over-stress by applying a voltage to the function circuit's pin which is sufficient to forward bias the diode. If no current flows after a sufficient biasing voltage is applied to the pin, it is a definitive indication that the function circuit may have been over-stressed.
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