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THS3095 is overheating

Other Parts Discussed in Thread: THS3095

Hi, i am using THS3095 as shown on a picture below

Both outputs is OK, but all amplifiers becoming extremely hot in a few minutes after power up, even without input signals (inputs are grounded). Output loads are larger than 1K. Input signals is sine wave 9Vpp at 100kH.

Is there any problems with schematic or i need to search elsewhere?

  • Sergey,

    This circuit generally seems ok.  There are a couple of things I would mention.

    1) The noninverting input of Buffer is currently acting as a capacitive load on the output of Buffer 2.  Though it is small, it could cause stability problems for Buffer 2.  I would recommend adding a small series resistor (20ohms or so) directly at the output of Buffer 2 to isolate it from Buffer, or eliminating Buffer altogether, as its purpose isn't immediately apparent in this circuit.

    2) You might consider reducing your loads on all four amplifiers from their present 1kohm values to between 100 and 500ohms.  Larger loads can also contribute to instability in current feedback amplifiers.

    3) If you try these things and the overheating continues, I would be inclined to believe it is a layout issue, in which case we can review your layout files for potential issues.

  • Thank you for quick answer!

    Problem was partially solved by adding a 100 ohms series resistor and balancing input signal.

    Amplifiers still heated, but much less. Temperature is not critical.