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

This paper describes a 1-V wide-input range and high linearity transconductance input stage that uses poly resistor and input-impedance boosting technique. Using the proposed transconductor, an op amp and a differential difference amplifier (DDA) were implemented in a 1.2-/spl mu/m CMOS process. The transconductor has a total harmonic distortion (THD) of less than -60 dB for an input swing of 400 mV at 10 kHz. The op amp 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 of 600 mV at 10 kHz.