The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 07, 2001
Filed:
Jan. 10, 2000
Bert L. Fransis, San Diego, CA (US);
John Francis O'Connor, San Diego, CA (US);
Conexant Systems, Inc., Newport Beach, CA (US);
Abstract
An amplifier circuit including a novel degeneration input stage that permits a low Noise Figure and superior linearity to be achieved in combination. The amplifier is suitable for use in fully integrated direct-conversion tuner circuits, and provides continuously variable gain functionality implemented by steering current away from an output load of the amplifier through differential transistor pairs located in the current signal paths of an input stage. Voltage headroom problems are avoided by placing the attenuation resistors of the degenerated input stage in the signal path, such that there is little or no DC voltage drop across the resistors. Further, this arrangement permits very accurate on-chip matching to an off-chip signal source. The distribution of IP,values over the gain range of the amplifier, as well as gain and NF characteristics, are dependent on resistor ratios rather than absolute values. These amplifier characteristics are thus largely temperature and process independent. In one embodiment of the invention, separate voltage supplies, ground connections and bias circuits are provided for different portions of the circuitry in order to improve noise immunity and reduce coupling of an input signal to the output of the amplifier circuit.