The OP-amplifier with offset cancellation circuit

For the data drivers of TFT-LCDs with high gray-scale above 8-bit, OP-Amps with high voltage accuracy less than 1 mV, is needed. Accordingly, the offsets voltages of the OP-Amps should be compensated in order to achieve the accuracy. In this paper, we present an asymmetrical differential input circuit with common mode feedback (CMFB) circuit, which reduces the offsets. The OP-Amp with the proposed circuit shows the systematic offset voltages less than 100 /spl mu/V in whole operating ranges. Furthermore, the random offsets also can be compensated by the proposed circuit.