Need Help with a INA Amplif

Discussion in 'General Electronics Chat' started by Giovanni, May 20, 2008.

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  1. Giovanni

    Thread Starter New Member

    May 20, 2008
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    Hi everybody, i'm new on this forum; i'm in need of help using an INA 52063. I use it as a 2nd stadium after a transimpedance amplifier and the problem is that when i turn on the DC generator the amplifier heats up and breaks .

    The layout used is the same shown in the application notes of the datasheet, and the supply is +5V. I've also added a 50 ohm parallel resistor at the output for impedance matching.

    Thanks for the help^^
     
  2. SgtWookie

    Expert

    Jul 17, 2007
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    What is your input signal level?

    What is the thickness of your PCB?

    If you're up in the GHz region, you'll have to plan your PCB traces pretty carefully to get a good impedance match.
     
  3. Giovanni

    Thread Starter New Member

    May 20, 2008
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    For my application i need to work around 20/30 Mhz so i use a 20 MHz 100mVpp input signal for testing. Do you think it could be a matching problem?
    My PCB is a double sided approx 1.5 mm thick...
     
  4. SgtWookie

    Expert

    Jul 17, 2007
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    100mV pp? :eek: That's what's killing it.
    Absolute maximum input power is +13 dBm, or 4,467 uV.
    You're feeding it 40 dBm, or 100,000uV.
     
  5. Giovanni

    Thread Starter New Member

    May 20, 2008
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    How do you obtained these values? I thought +13dBm was equal to 1V ( 10^(13/10) => approx 20 mW so V=sqrt(20mW*50ohm) => approx 1V)

    However i've noticed that even if i don't give a singnal in input, when i supply the IC it burns out even at +4V... help! :(
     
  6. beenthere

    Retired Moderator

    Apr 20, 2004
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    Can you post the layout of your printed circuit board and indicate the component values? The schematic would be helpful as well.

    The chip burning with no signal makes it likely that it is going into a destructive oscillation, possibly due to layout or wrong value components.
     
  7. JoeJester

    AAC Fanatic!

    Apr 26, 2005
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    dBm is referenced to 1 milliwat. 100,000 uV is neg 7 dBm (-6.9897).
     
  8. Giovanni

    Thread Starter New Member

    May 20, 2008
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    Non-productive comment removed.
     
    Last edited by a moderator: May 26, 2008
  9. hgmjr

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    Jan 28, 2005
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    ..........
     
    Last edited by a moderator: May 26, 2008
  10. Dave

    Retired Moderator

    Nov 17, 2003
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    Some people in life speak foreign languages; for everyone else there's Babel Fish.

    Dave
     
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