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Driver amplifiers with low noise standby mode characteristics

  • US 5,994,955 A
  • Filed: 06/26/1998
  • Issued: 11/30/1999
  • Est. Priority Date: 06/26/1998
  • Status: Expired due to Fees
First Claim
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1. A driver amplifier operable to enter a standby mode, the driver amplifier comprising:

  • a first amplifier having an input, an output, and a bias control input, the first amplifier operable to generate a first differential signal at the first amplifier output, the first differential signal being a function of signals applied at the first amplifier input and the first amplifier bias control input;

    a second amplifier having an input, an output, and a bias control input, the second amplifier operable to generate a second differential signal at the second amplifier output, the second differential signal being a function of signals applied at the second amplifier input and the second amplifier bias control input;

    a bias generator circuit coupled to the first amplifier bias control input and the second amplifier bias control input, the bias generator operable to place the first and second amplifiers into a standby mode wherein the first and second amplifiers are turned off, the bias generator operable to place the first and second amplifiers into an active mode wherein the first and second amplifiers are turned on,wherein the bias generator circuit, the first amplifier, and the second amplifier operate together such that when the bias generator transitions the first and second amplifiers between standby and transmit modes the first and second amplifiers transition simultaneously such that a magnitude of transient noise generated by the first amplifier is substantially similar to a magnitude of transient noise generated by the second amplifier, the driver amplifier further operable such that the first and second amplifiers draw substantially no current when the first and second amplifiers are in the standby mode.

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