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OPA4314: Amplifiers forum

Part Number: OPA4314

Hi team,

There is the following description in the data sheet though,  Is it okay to apply more than 0.5V at input pins under no supply condition if the current to the input pin is 10 mA or less?

My customer plan to use following circuit. Due to their power sequencing, 3.3V rail will be turned off earlier than 5V rail.

Regards,

Takashi Onawa

  • Hi team,

    supplement a little.

    My customer wants to know whether the device might get damage by the voltage and current or not.

    Regards,

    Takashi Onawa

  • Hi Takashi,

    Please note that you're referring to Abs max table. As long as your current is limited to less than 10mA, you will not damage your op amp. But please note that the recommended input common-mode voltage for this device is (V-) - 0.2V to (V+) + 0.2V. Anything beyond this we do not guarantee normal behavior by the op amp. 

    The Abs max table is listed to show the limits beyond which you can damage your op amp. Please refer to the Electrical Characteristics table to find out the limits of normal op amp behavior. 

    Best Regards,

    Bala Ravi 

  • Hi Ravi-san,

    Let me confirm one more point just in case. 

    There is a ESD diode between input pins and VCC, right?
    I think 3.3V amp's input voltage would go down following VCC by the diode if 3.3V rail tuned off in the circuit at first. 

    I'm understanding that the diode would be tolerant up to 0.5V * 10mA power dissipation from the description in the datasheet though, is this understanding correct? 

    Regards,

    Takashi Onawa

  • Hi Takashi,

    That's right the inputs are diode clamped to the supply rails. Please note that 5mW power dissipation is the limit for the diodes and will make sure your op amp isn't damaged but your op amp may still show strange behavior if operated beyond Electrical characteristics table limits. 

    Best Regards,

    Bala Ravi

  • Hi Ravi-san,

    Thanks, I understood.

    Regards,

    Takashi Onawa