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LMP2012QML-SP: What is the maximum input overvoltage the device can tolerate if the input current is limited?

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Replies: 2

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Part Number: LMP2012QML-SP

The data sheet for the LMP2012 specifies that the input voltage must not extend more than 0.3 V outside the supply voltage. This is a common specification as it prevents parasitic p-n junctions from becoming forward-biased. However, if the input current is limited (by a resistor in series with the input, for example), I assume the device will not be damaged.

Q1: Is my assumption correct?

Q2; If yes, what is the maximum allowable input current the device can tolerate without being damaged?

Nigel

Regards,

Nigel

  • In addition to the Abs Max spec for input voltage not to extend more than 0.3V outside of power rails,  the abs max table also includes a spec for maximum input current not to exceed 30mA.  Therefore, limiting current to something less than 30mA is required to avoid electromigration degradation of metal traces.  Although the presence of both a max voltage and a max current specs implies that if current is limited then exceeding the voltage spec is OK, the datasheet does not explicitly state this.  Your assumption may or may not be valid but we cannot guarantee device will be OK. 

    Thanks

    Christian 

  • Hi Nigel,

    the best way is to clamp input overvoltages to the supply rails by the help of a low leakage current diode or a special low leakage JFET and to additionally limit the resulting input current into the OPAmp to about one tenth of the maximum input current rating by the help of a simple resistor. Of course, the current through the clamping diodes should also be limited to a safe level.

    Kai