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:
Oct. 26, 2010
Filed:
Oct. 16, 2008
Nobuhiro Shiramizu, Musashino, JP;
Toru Masuda, Kokubunji, JP;
Nobuhiro Shiramizu, Musashino, JP;
Toru Masuda, Kokubunji, JP;
Renesas Electronics Corporation, Kawasaki-shi, JP;
Abstract
The variable gain amplifier includes a bias circuit (BC), a matching circuit (MC), a variable gain resistive feedback amplifier (FA)and an output follower (EA). The resistance values of the load resistance Rc and feedback resistance Rf are changed in cooperation. In a case of making the load resistance Rc a high resistance to set the low noise amplifier to a high gain, the feedback resistance Rf is also made a high resistance, the feedback time constant τfb(c)≈2π·RfCbe/(1+gmRc) of the closed loop of the resistive negative feedback amplifierbecomes substantially constant, and then the amplifier has a gain small in frequency dependency over a wide bandwidth. In a case of making the load resistance Rc a low resistance to set the low noise amplifier to a low gain, the feedback resistance Rf is also made a low resistance. The feedback resistance Rf with the low resistance increases the negative feedback quantity, and thus the amplifier is set to a low gain. Also, the load resistance Rc is made a low resistance, and the feedback time constant τfb(c) becomes substantially constant. The gain is not lowered further in a high frequency region.