| 摘要 |
<p>A step gain-variable CMOS amplifier is based on the basic structure of a differential amplifier including an input pair of transistors (M1,M2), a bias current generator (M11) connected between a common source node of the input pair of transistors and the ground node of the circuit and a pair of load transistors (M9,M10) of same type of conductivity of the input pair connected between the supply voltage node and, respectively, to the drain nodes of the input transistors. The novel structure according to this invention comprises a plurality of either the input pairs of transistors (M3,M4,M5,M6,M7,M8) or of load pairs of transistors connectable in parallel for increasing the effective width of the resultant transistors. A plurality of path selection pairs of switches may be programmably closed for connecting in parallel the selected pairs of either input transisitors or of load transistors. <IMAGE> <IMAGE></p> |
