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Radio-frequency switch circuit and semiconductor device

  • US 7,391,282 B2
  • Filed: 11/17/2005
  • Issued: 06/24/2008
  • Est. Priority Date: 11/17/2004
  • Status: Expired due to Fees
First Claim
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1. A radio-frequency switch circuit for controlling flow of a radio-frequency signal, comprising:

  • a plurality of field-effect transistors inserted between an input/output terminal and a ground terminal and connected in series, a radio-frequency signal being input and output through the input/output terminal; and

    a plurality of resistance elements, wherein each of the plurality of resistance elements has two terminals, one of the two terminals is connected to a gate electrode of a corresponding one of the plurality of field-effect transistors, and a control voltage for switching an ON state and an OFF state of the corresponding field-effect transistor is applied to the other of the two terminals,wherein one of the plurality of resistance elements connected to a gate electrode of one of the plurality of field-effect transistors connected to the input/output terminal has a highest resistance value among the plurality of resistance elements, and wherein;

    first to n-th (n is an integer of 2 or more) field-effect transistors are connected in series and in order of first to n-th between from the input/output terminal to the ground terminal; and

    resistance values Rgs(1) to Rgs(n) of first to n-th resistance elements connected to gate electrodes of the first to n-th field-effect transistors are set based on the following expression;


    Rgs(1)>

    Rgs(2)≧

    . . .

    Rgs
    (n−

    1)≧

    Rgs(n).

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