op amp

Discussion in 'General Electronics Chat' started by soudabeh, Jul 30, 2011.

  1. soudabeh

    Thread Starter New Member

    Jul 4, 2011
    3
    0
    hello
    I'm looking for an op amp which frequency bandwidth is higher than 4Mhz & its gain is selectable (from 5 to 20).plaese help me.
    thanks in advance......
     
  2. praondevou

    AAC Fanatic!

    Jul 9, 2011
    2,936
    488
    there are so many of them. a simple search in digikey gives more than 2000 items.

    - open www.digikey.com
    - type "opamp" in the search field
    - click on Linear - Amplifiers -Instrumentation, OP Amps, Buffer Amps
    - press and hold Ctrl and select all frequencies higher than 4MHz under "Bandwith"
    - click "Apply"
     
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  3. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Well, there are lots of opamps with GBW > 4MHz.
    How about an LM6132 or MC33078?

    As far as selectable gain, all you'd need to do is use a selectable feedback network to get the gain you wanted, like this:

    [​IMG]

    Note that 90k is not a standard value of resistance, but you can use a 68k and 22k in series, or two 180k resistors in parallel to get 90k Ohms. Or you could use all 30k Ohm resistors; two in parallel to get 15k, and three in series to get 90k.
     
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  4. Ron H

    AAC Fanatic!

    Apr 14, 2005
    7,050
    657
    S1 and S2 labels need to be swapped, like this:
     
    Last edited: Jul 31, 2011
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