| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor integrated circuit for communication capable of completing an offset canceling operation within a predetermined time. SOLUTION: In a high-gain amplifier circuit, in which a plurality of differential variable gain amplifiers PGA 1-PGA 3 and a plurality of filters LPF 1-LPF 3 are connected in multi-stages to amplify reception signals; and offset compensation circuits OFC 1-OFC 3 are constituted in the respective variable gain amplifiers, in such a way that switch elements are provided in parallel to resistor elements forming the filters, and the order of each of the filters can be switched, depending on turning on/off. A low-order filter is used for a low-pass filter to compensate offset, then a switching element for short circuit is turned off, to quickly make outputs of the variable gain amplifiers the coverage. After that, a switching element for switching the order is turned off, to switch the low-pass filter to a high-order filter, and an output of the variable gain amplifier on the preceding stage is made to be inputted to the variable gain amplifier on the later stage, to perform offset compensation for the post stage. COPYRIGHT: (C)2004,JPO
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