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:
Nov. 06, 2012
Filed:
Dec. 03, 2010
Gregory A. Fung, Fremont, CA (US);
Gregory A. Fung, Fremont, CA (US);
Linear Technology Corporation, Milpitas, CA (US);
Abstract
An actual linear amplifier distorts an input signal, such as an RF signal, and generates third order intermodulation (IM3) products. In an embodiment of a Class A amplifier, the linear amplifier is a bipolar, common emitter-configured (CE) transistor using a cascode transistor to provide a fixed collector bias voltage to the CE transistor. The CE transistor has a transconductance vs. base-emitter voltage (V) characteristic which, when plotted, shows a transconductance that increases with an increasing Vto a maximum, then drops, then tapers off, wherein there is an inflection point between the maximum transconductance and where the transconductance tapers off. A DC bias circuit provides a DC bias voltage to the base of the CE transistor that causes the CE transistor's operating point to track the inflection point over a range of temperatures. This operating point causes the IM3 products to be greatly reduced.