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:
May. 17, 2011
Filed:
Dec. 18, 2007
Jose Cabanillas, San Diego, CA (US);
Prasad S. Gudem, San Diego, CA (US);
Namsoo Kim, San Diego, CA (US);
Cristian Marcu, Windsor, CA (US);
Anup Savla, San Mateo, CA (US);
Jose Cabanillas, San Diego, CA (US);
Prasad S. Gudem, San Diego, CA (US);
Namsoo Kim, San Diego, CA (US);
Cristian Marcu, Windsor, CA (US);
Anup Savla, San Mateo, CA (US);
QUALCOMM, Incorporated, San Diego, CA (US);
Abstract
A differential low noise amplifier (LNA) involves two main amplifying transistors biased in saturation, and two cancel transistors biased in sub-threshold. In one example, the gates of the cancel transistors are coupled to the drains of main transistors, in a symmetrical and cross-coupled fashion. The main transistors are source degenerated. Because the gates of cancel transistors are not coupled to the differential input leads of the LNA, the input capacitance of the LNA is reduced. Noise introduced into the LNA output due to the cancel transistors being biased in the sub-threshold region is reduced because there are two stages. The first stage involves the main transistors, and the second stage involves the cancel transistors. By increasing the gain of the first stage and decreasing the gain of the second stage, overall LNA gain is maintained while reducing the noise that the sub-threshold biased transistors contribute to the LNA output.