| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To set individual devices at their optimal operating points to bring out intrinsic capabilities of the devices even if there exist variations in process lot, wafer or temperature. <P>SOLUTION: In a separated state in the range of high frequencies from a main FET 1 to which high-frequency signals are input, a monitoring FET 2 is formed in the same chip as that where a main FET 1 is formed. By detecting a saturation current of the monitoring FET 2, a saturation current of the main FET 1 is monitored to hold the saturation current consistently at an operating point of a given rate of the saturation current. A ratio of a value R<SB>1</SB>of a first resistance 11 and value R<SB>2</SB>of a second resistance 14 is selected to satisfy R<SB>1</SB>/R<SB>2</SB>=(Wg<SB>2</SB>/Wg<SB>1</SB>)/(x/100) where defining a main FET 1 gate width as Wg<SB>1</SB>, a monitoring FET 2 gate width as Wg<SB>2</SB>and a ratio of the operating point to the saturation current as x%. Then, a gate voltage of the main FET 1 is controlled so that drain voltages of the main FET 1 and monitoring FET 2 become equal to each other. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
