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Is the IC defective if input voltage of uPC272 comparator is strange?

Latest Updated:12/01/2011

Question:

The input voltage of the uPC272 comparator is strange.
One of the input voltages is 0 V. If an attempt is made to apply 9 V to the other input pin, a large amount of current flows.
Is this IC defective?

Answer:

The differential input voltage (VID) of the uPC272 is 5 V. Therefore, the voltage difference between the input pins must be kept below 5 V.
This product uses ordinary transistors for the differential amplifier for the input to increase the speed.
Note that its differential input voltage is limited as a result.
If this value is exceeded, the voltage between the emitter and the base of the input transistor will be exceeded reverse breakdown voltage and the transistor will be damaged.
If this voltage is exceeded even just once, the operational amplifier will be internally damaged (such as a drop in hfe of the input transistor) even though it seems to operate correctly. Do not use such a compromised product.
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