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LMV358 Input Range

Leonardo
Prodigy 130 points
Other Parts Discussed in Thread: LMV358

Hello,

It is safe to rely on clamping diode and allow continous 6v - 10v range on one differential input of LMV358 limiting current with one 10k resistor?

Thank you

- Power supply of op-amp is 5v

- Op-amp is used like comparator and the other differential input is stuck at 3.3v

  • 0
    TI__Guru*** 140136 points

    Leonardo,

    10V through 10k to input with diode to VCC. (10V - (5V + 0.7V))/10k = 0.43mA.
    This input current is not a concern provided the 5V line can absorb the current.


  • 0 in reply to Ron Michallick
    Prodigy 130 points

    Thank you very much, my fear was that so life of op-amp is reduced

  • 0
    TI__Mastermind 49966 points

    Hi Leonardo,

    As long as the current into the pin is limited to less than a milliamp or two it should be fine...though not ideal.

    10V-5V=5V, 5V/10K=500uA, so 10K is good enough.

    An external Schottky diode is recommended to take the stress off the internal ESD diode if this condition is expected for long periods.

    Also beware that it is possible to back-feed voltage into the supply line if the input current is high enough, and the supply loads are low enough. Most regulators cannot sink current, so the regulator cannot regulate the supply voltage if it is *higher* than the specified output voltage (the regulator output transistor turns off).

    Regards,