OTA linearization via electronically-programmable current mirrors

A simple electronically programmable MOS current mirror is presented which provides variable amplification and at the same time improves the linearity of currents generated by a simple differential pair. Analysis of this linearity-improvement/g_m-a scheme is verified experimentally. The combination of a simple differential pair and simple programmable current mirrors has been shown to yield an OTA (operational transconductor amplifier) which allows an additional degree of freedom in g_m adjustment, i.e., a g_m adjustment in a differential-pair-based input stage. It also allows an input signal greater than that which can be obtained from a comparable simple-differential-pair and fixed-current-mirror combination