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OPA196: Suplly the OPA196 with a 9 V battery

user5990299
Prodigy 70 points
Part Number: OPA196

Hello together,

can I suplly the OPA196 with a normal 9 V Battery, or I have to consider anything?

Do I have to restrict the supply current general?

Thanks for helb,

Marvin

  • 0
    Guru 140200 points
    Hi Marvin,

    yes, see section 6.3 of datasheet.

    But keep in mind, that batteries suffer from an increase of source resistance when getting older. So, you might want to enhance the supply decoupling a bit. This is the more true the more load current the OPAmp is drawing. I would recommend to add a 10...100µ aluminium electrolytic to the obligatory 100nF decoupling cap.

    Kai
  • 0 in reply to kai klaas69
    Prodigy 70 points
    Thank you for the fast help.

    Ok, and I do not have to limit the suplly current, right?

    Marv
  • 0 in reply to user5990299
    Guru 140200 points
    Hhm, why do you want to limit the supply current?

    Kai
  • 0 in reply to kai klaas69
    Prodigy 70 points
    I do not want to limit the supply current.
    I just destroy one of my OPAs and then I thought mhh do I have to limit the supply current?
    Sorry it is my first time that I work wirh OPAs :).

    Know I supply my OPA with the 9 V battery and it's working good, unless the Offset Voltage.
    I have a Multimeter (HP3458A) which can measure DC Voltage in a Range of a few Mircovolt and so I want to measure the Offset Voltage at the Output when I short the Inputs. but the Output Voltage is far away for the specific Offset Voltage it stands in the datsheet.

    Maybe you or somebody else can give me a advice to handle this problem.

    Marv
  • 0 in reply to user5990299
    Guru 140200 points

    Hi Marvin,

    can you show a schematic of your circuit?

    Kai

  • 0 in reply to user5990299
    TI__Guru* 93105 points

    Hello user5990299,

    The OPA196 certainly can easily be powered by a single 9 V battery. You shouldn't have to provide any sort of current limiting circuit because the OPA196 operating current alone is very low; at most 250 uA. Any load you drive with the OPA196 will require current be sourced or sunk from the op amp output. That load current originates from the 9 V battery and flows from/into one of the OPA196 supply pins.

    Just exactly how much current the OPA196 can provide is limited and function of the output stage electrical characteristics and operating temperature. The OPA196 datasheet Typical Characteristics graphs in Figures 6 and 7, Output Voltage Swing vs Output Current, provide a good representation of just how much output current can be expected from the OPA196. Normally, a precision op amp such as the OPA196 is used to drive a light load such as 10 kilohms, or 2 kilohms, and the output current is low. A 9 V battery can easily handle that total operating current and output load current.

    Make sure that the OPA196 is being operated within its linear common-mode input voltage range, and linear output voltage swing range. If the op amp is biased in such a manner that the output is up against one of its swing rails, it won't be in its linear operating range and the voltage offset will be outside its specified range. It would be helpful if we could see your test circuit as Kai mentioned.

    If you would like some help with understanding the voltage offset of an operational amplifier, have a look at the TI Precision Labs - Op amps series, Section 2. I think that may be help you with your voltage offset measurement:

    https://training.ti.com/ti-precision-labs-op-amps

    Regards, Thomas

    Precision Amplifiers Applications Engineering