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SEEKING AN OP-AMP CONFIGURATION THAT CAN BE USED FOR SUMMING 4 OR MORE INPUT SIGNALS AT 1GHZ

arthur williams73
Intellectual 390 points

A conventional op-amp will not has sufficient open-loop gain at 1GHz to create a virtual ground at the inverting input at 1GHz. Is there another architecture other than the traditional which uses the inverting input for summing?

  • 0
    Guru 140200 points

    Hi Arthur,

    a simple resistive voltage divider is usually used for this.

    Kai

  • 0 in reply to kai klaas69
    Intellectual 390 points
    Using a voltage divider in a resistive power splitter configuration the summed output will be a function of whether other ports which may be unused are terminated or not. At lower frequencies one would use a conventional op-amp and sum the input signals into the inverting input. The output of the amplifier would be the summation of all input signals that are present (with a feedback resistor present). With a pure resistive divider power splitter the output will depend on how many input whether used or not are terminated or an open circuit. The inputs are not totally isolated.
  • 0 in reply to arthur williams73
    Guru 140200 points
    Hi Arthur,

    can you terminate the unused inputs with 50R resistors to ground?

    Kai