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TL331: GND pin spec requirement?

Part Number: TL331
Other Parts Discussed in Thread: LM311, LM6511


May I know the TL331 GND pin level spec?

Is it okay to use negative voltage? If yes, what is the limitation? -36V or VCC-GND= with in 36V Abs.?

Thanks and Best regards,


  • All voltages are measured relative to GND. In your circuit, that voltage might be assigned a different value (measured relative to the power supply's ground), but from the point of view of the device, GND always is 0 V.

    VCC must be larger than GND, up to 36 V. The inputs can be up to −0.3 V lower than GND, or up to 36 V above GND. The difference between the two inputs can be up to ±36 V.

  • Hi Tiger,

    yes, you can do so. But the difference between the positive and the negative supply voltages must not exced 36V. And the absolute maximum ratings and the common mode input voltage range have to be adapted accordingly.

    An example: When you use a bipolar supply voltage of +/-12V, then the common mode input voltage range translates to -12V ... +10.5V.


  • Hello Tiger,

    As Kai and Clemens have said, Yes, you can use the TL331 on split supplies.

    So long as you are aware of these items:

    1. Total supply voltage (V+ - GND pin) must be less than 36V (As Clemens discussed).

    2. Input voltages should not be less than the GND pin and up to 2V below V+ pin (as Kai showed).

    3. Realize that the output will be pulled low to the GND pin potential, and NOT the system ground. So some level shifting of the output may be necessary for ground referenced logic levels.

    Devices specifically designed for bipolar supplies and ground referenced logic output are the LM311, LM319 and LM6511.