Opamp Bandwidth - LargeSignal, Small Signal

Discussion in 'Homework Help' started by velu, Oct 15, 2009.

  1. velu

    Thread Starter New Member

    Oct 15, 2009
    Hi, Can anyone explain the OpAmp large & small signal bandwidth from high level and also the detailed procedure to measure it with the lab setup like an example given below?

    (Is the following steps are correct for large sigal Bandwidth measurement ?)

    Step 1: Set Opamp Power Supply .
    Step 2: Set unity gain feed back.
    Step 3: Set a sine wave with 60Hz frequency and tweak the amplitude to achieve the max output swing (Vopp).
    Step 4: Measure the Output Volatge Peak-to-Peak as Vopp_max.
    Step 5: Sweep the frequency ( in log scale) and measure the corresponding Voltage output (Vopp) for each step until the Vopp falls below 3dB level (0.707 *Vopp_max).
    Step 6: Log the frequency.
  2. Audioguru

    New Member

    Dec 20, 2007
    an opamp can have voltage gain at fairly high frequencies. But its output cannot swing fast enough when the amplitude is high.

    For example, a 741 opamp has a max voltage gain of 10 at 100kHz but if its output is 28V p-p its level drops above 9kHz due to "slew-rate-limiting". The sine-wave output changes into a triangle wave as it tries to slew.

    Many audio opamps like the TL07x have an output that is 30V p-p at up to 100kHz.
    Last edited by a moderator: Oct 25, 2009
  3. bertus


    Apr 5, 2008

    Take a look at the attached PDF from TI.