In our experiments,we found that the input voltage to the signal input pin was 5.54V, and the input current was 0.2mA.
Does this results exceed the absolute maximum ratings?
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all these specifications have to do with the ambient temperature and die temperature. The higher the temperature the lower the voltage dropping across the internal protection diodes and the higher the risk that a damaging current will flow into the chip when the input voltage exceeds the supply rails. Because of that you may see only a rather small current when exceeding the supply rails by 0.5V at room temperature. But when you do that at elevated temperatures the input current will dramatically rise, concretely spoken in an exponentially way.
Another cause for observing a rather small input current can be manufacturing tolerances. It's also possible that the internal protection diodes became already damaged by an earlier over-current event. This would be bad because then you would have less protection at this pin now.
So, always add an external current limiting resistor when the input voltage can exceed the supply rails.
And in order to reduce the risk of ending up with latch-up or lock-up, limit the input current to well below 10mA. The 10mA limit is only to prevent damage from the input protection diodes. But to prevent latch-up or lock-up the input current should be limited to a way smaller input current, best below 1mA. If you cannot limit the input current to these low values and there is the risk of latch-up or lock-up, then an additional protection circuit should be planned, as discussed here:
When is the risk of latch-up or lock-up?
When the input voltage exceeds the supply rails at power-down and you power-up the OPAmp with the input voltage still exceeding the supply rails. This is a scenario when latch-up or lock-up can often be observed. And especially insane are negative input voltages, because these can make a highly unwanted current to flow through the substrate of die, a current which would never flow during normal operation.
Hello ?? ??,
If the current is low because the impedance of the input source including series resistors in high then the current won't exceed. The key is that the current is limited externally. The input is a 'diode' so don't expect it to limit the current.
This input is outside the common mode range , I suggest reducing the voltage.
if the input voltage can exceed (V+) + 0.5 V, then you should use a series resistor to limit the current.
(V+) is 5V,and we use 10kΩ series resistor for current limiting.
Should the resistor be changed to a larger resistance?
Sorry for my poor writing...
Our concern is whether it is okay for the input voltage to exceed (V +) + 0.5V with a 10kΩ series resistor.
In our experiment, the input voltage to the input pin was 5.54V under the condition that the input voltage to the 10kΩ series resistor was 7.5V.
In this situation,should the resistor be changed to a larger resistance?
No change is necessary; in that experiment, the current was much smaller than 10 mA. That 0.54 V is the forward voltage of the clamping diode. The (V+) + 0.5 V limit applies only when you do not have any current limiting.