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Op Amp Unit Gain at frequency 1 MHz

Discussion in 'General Electronics Discussion' started by Faris Ahamad, Dec 31, 2012.

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  1. Faris Ahamad

    Faris Ahamad

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    Dec 31, 2012
    Why Op Amps have unit gain at frequency 1 MHz?Pls explain in such a way that even a beginner in the topic of Op Amp.can understand
     
  2. duke37

    duke37

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    769
    Jan 9, 2011
    Different op amps will have different gains at 1MHz.
    The gain drops as the frequency rises, you will need to go to the data sheet for the particular op amp you wish to use.

    I think that the frquency response is due to the inherent capacitors in the active devices. To get a high frequency op amp, go for one with a large gain/bandwidth product.
     
  3. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,448
    2,809
    Jan 21, 2010
    It is also deliberately introduced to help prevent spurious oscillation. Remember that these devices have high gain, and that in a circuit there may be parasitic capacitances which introduce positive feedback. Since the amount of feedback will increase with frequency, the device (if it had a constant gain from DC to daylight) would oscillate at some high frequency. The roll off of gain with increasing frequency helps ensure that at the frequencies where this parasitic positive feedback becomes larger, the gain is low, helping to prevent oscillation.

    What this means is that when you use a device with a low gain bandwidth product, you can be quite messy with your layout and still achieve stability. As you get higher and higher spec devices, your layout (and design) needs to be higher spec too.
     
  4. Faris Ahamad

    Faris Ahamad

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    0
    Dec 31, 2012
    so, there is no speciality for 1 MHz value in general?
     
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