One of the origins of harmonic distortion in current mirrors is the inevitable mismatch between the mirror transistors. In this brief we examine both single current mirrors and complementary class AB current mirrors and develop analytical expressions for the mismatch induced harmonic distortion. The expressions are verified through simulations and are used for a discussion of the impact of mismatch on harmonic distortion properties of CMOS current mirrors. The distortion model is combined with well known statistical models for the device mismatch in order to establish a relation between geometrical parameters, distortion and production yield. It is found that distortion levels somewhat below 1% can be attained by carefully matching the mirror transistors but ultra low distortion is not achievable.
|Journal||IEEE transactions on circuits and systems - 2, Analog and digital signal processing|
|Publication status||Published - 1999|