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opamp temperature resistant circuit

Discussion in 'General Electronics Discussion' started by hellsnomad, Oct 10, 2010.

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  1. hellsnomad

    hellsnomad

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    Oct 10, 2010
    Dear all, for my project i need to have no changes in the temperature in an opamp non inverting amplifier, due to the offset voltage.

    can someone please recommend any type of circuit or components one can use to have no variation in this opamp cct.

    thank you
     
  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Jan 21, 2010
    That's not too clear.

    It sounds like you're asking how to prevent the offset voltage heating an op-amp. That doesn't really make sense.

    Are you after an op-amp with minimal change in offset current with temperature? Or perhaps a method of keeping an op-amp at a particular temperature to prevent temperature related changes in offset voltage?

    Perhaps you should also explain why you need this, as that may have significant bearing on the solution.

    I presume you're doing something with a DC amplifier.
     
  3. hellsnomad

    hellsnomad

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    Oct 10, 2010
    I am amplifying a dc voltage of less than 5mV to 3V, coming from a load cell in order for me to enter an ADC of an 8051 microcontroller.

    I need as you said a method of keeping the op-amp at a particular temp in order to prevent changes in the o/p voltage due to the offset voltage.

    thank you
     
  4. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Jan 21, 2010
    Have you considered one of the chopper stabilised op-amps?

    It sounds like the frequency response would not need to be high, and these devices are well suited to this sort of thing.

    Thiss one (selected largely at random) has 0.7uV input offset, for example.
     
  5. hellsnomad

    hellsnomad

    3
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    Oct 10, 2010
    Never worked with this category of op-amps.

    Thank you very much!!I will consider buying this type of op-amp since to the low input offset. The next step is for me to check the sampling rate of the ADC to check if i have to apply a Low pass filter after this cct.

    Thank you
     
  6. NickS

    NickS

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    Apr 6, 2010
    Since no rules have been given to the contrary I will throw this out.

    To keep temperature regulated on loose parts we once built a nylon well around the circuit and potted the parts in thermal epoxy which was then attached to a finned heatsink. It worked well but board re-work was not an option.
     
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