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TLV2381: Negative input voltage

Ryuuichi machida
Guru 11705 points
Part Number: TLV2381

Hello,

I would like you to confirm whether input and output spec for TLV2381.

* According to datasheet, it seems that user can input both negative and positive supply.

And also, I can find figure which both negative and positive voltage is input .

From above two information, I assume that this device is corresponded to dual supply.

However, I have following question.

1. According to above, common mode is defined as "-0.2 to Vs+0.2", is it correct information ?

2. When user require to use dual supply, can user input positive supply to "Vcc" pin and negative supply to "GND" ?

Best Regards,

  • 0
    Guru 140200 points
    Hi Ryuuichi,

    yes, "-0.2 to Vs+0.2" is correct. But it refers to a single supply voltage. For a bipolar supply voltage this means that the input voltages may exceed the supply voltages by only 0.2V. So, for a +/-5V supply voltage, e.g., the input voltages must be between within -5.2V...+5.2V.

    And yes, the positive supply voltage is to be connected to the VDD pin and the negative supply voltage must be connected to the GND pin.

    Kai
  • 0 in reply to kai klaas69
    Guru 11705 points
    Hello,

    For a bipolar supply voltage this means that the input voltages may exceed the supply voltages by only 0.2V. So, for a +/-5V supply voltage, e.g., the input voltages must be between within -5.2V...+5.2V.

    Is above correct ?
    If above case is correct, I'm not sure why you do NOT describe "-0.2 + GND to Vs + 0.2" ?
    I wonder why you describe "absolute value" for minimum spec despite supporting dual supply.

    Best Regards,
  • 0 in reply to Ryuuichi machida
    Guru 140200 points

    Hi Ryuuichi,

    Hhm, I have no idea what you mean... :-)

    By "supply voltage" I mean the voltage which is connected to pin "VDD" and to pin "GND". By "input voltage" I mean the voltage which is connected to pin "IN+" and to pin "IN-":

    Kai

  • 0 in reply to kai klaas69
    Guru 11705 points

    Hello,

    What I pointed out is common mode voltage.

    According to datasheet, VICR(input common mode range) is defined as "-0.2 to Vs+0.2".

    For a bipolar supply voltage this means that the input voltages may exceed the supply voltages by only 0.2V. So, for a +/-5V supply voltage, e.g., the input voltages must be between within -5.2V...+5.2V.

    However, you described as shown above in case of dual supply.

    I believe that this means that VICR is "-0.2+GND to Vs+0.2".

    However, I'm not sure why you describe VICR is "-0.2 to Vs+0.2" despite supporting dual supply.

    Can you understand my question ?

    BR, 

  • 0 in reply to Ryuuichi machida
    TI__Mastermind 24160 points
    Ryuuichi
    Your assumption is correct. VICR is "-0.2+GND to Vs+0.2" for single supply applications.
    Chuck
  • 0 in reply to Chuck Sins
    Guru 11705 points

    Hello Chuck-san,

     > VICR is "-0.2+GND to Vs+0.2" for single supply applications.

    We can also say same thing for dual supply application, right ?

    In case of dual supply application, negative voltage will be supplied to "GND" pin.

    Best Regards,

  • 0 in reply to Ryuuichi machida
    TI__Mastermind 24160 points
    Machida-san
    Yes, the negative supply would be connected to the GND pin and the positive supply would be connected to VDD. We should have labeled the GND pin VSS to make it more obvious. Sorry for the confusion.
    Chuck