Low-voltage opamp design and differential difference amplifier design using linear transconductor with resistor input

This paper describes a 1-V wide-input range and high linearity transconduct ance input stage that uses poly resistor and input-impedance boosting techn ique, Using the proposed transconductor, an opamp and a differential differ ence amplifier (DDA) were implemented in a 1.2-mu m CMOS process. The trans conductor has a total harmonic distortion (THD) of less than - 60 dB for an input swing of 400 mV at 10 kHz. The opamp and the DDA show a peak-to-peak output swing of 800 mV and a THD of less than -70 dB for an output swing o f 600 mV at 10 kHz.