New efficient offset voltage using digital cancellation techniques trimming

Operational amplifiers are very important basic building block in mixed analog-digital circuit design. The performance of these circuits is usually quoted in terms of input-referred offset voltage, power consumption, gain-bandwidth product, etc. The focus of this paper is a new set of techniques to reduce the input referred offset voltage. In this paper, two approaches to digitally trim the offset voltage of the first stage gain of operation amplifier are presented and discussed. Both approaches use a set of digitally programmed weighted current mirrors. The attractive features of the new techniques are: wide dynamic range, small silicon area, low power, and the ability to be adapted to provide auto-zero cancellation on the input-referred offset voltage.