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TLV9151: Signal input limit

Yen Nee Lee
Prodigy 120 points

Part Number: TLV9151

Hi,

From the datasheet as shown below, does the highlighted statement means that the signal input pins are allowed to exceed (V+)+0.5V if the current is <10mA?

In my design, the supply voltage to TLV9151 is 5V. However, we realized that the signal input may have the risk of exposure to a voltage of 6V. This line has a 150kOhm current limiter in front so the current is very small. Will it still damage the TLV9151?

Thanks. 

  • 0
    Guru 321790 points

    Yes, with a series resistor that limits the current to less than 10 mA, higher voltages are allowed.

    Please note that your power supply must be able to sink the current. But in your case, the current will be about 2 µA, which is not be a problem.

  • 0
    Guru 140200 points

    Hi Yen,

    no, this will not damage the TLV9151. But please note that you leave the specified common mode input voltage range (which is 0.1V beyond the supply rails) in this moment and the TLV9151 is not guaranteed to work properly then. If this is an issue in your application, install an external diode clamp to the supply rails with a suited current limiting resistor in series and install a voltage divider behind the diode clamp in front of the OPAmp.

    Kai

  • 0 in reply to kai klaas69
    TI__Mastermind 29640 points

    Hi Yen,

    I agree with Kai, an external diode clamp would be most beneficial in systems where you know that this problem can arise. Clemens is also correct that you need your power supplies to sink the current. Just make sure you fully understand the maximum voltage the input signal can reach. 

    I also want to add that while the Absolute Maximum Ratings are important, I usually stick to the Recommended Operating Conditions, since that's where we guarantee the device will perform as we have tested. 

    Best Regards,

    Robert Clifton 

  • 0 in reply to Robert Clifton56
    Prodigy 120 points

    Thanks for the recommendation. We will try to voltage divide it as adding a diode is not an option now.

    May i know what do you mean by the "power supplies need to be able to sink the current"? 

    Also, based on the chart below, can i say that the output is always max at V+ and the output current is very small <1mA at that point?

  • 0 in reply to Yen Nee Lee
    TI__Mastermind 29640 points

    Hi Yen,

    Normally the power supplies will have current flowing out to the op-amp. However during times when the input signal is 6V, the internal ESD diode at the input pins will turn on and current will flow from the input pin to the power supply. 

    Best Regards,

    Robert Clifton