A Novel Input Stage Based on DTMOS for Low-Voltage Low-Noise Operational Amplifier

In this paper, a novel input stage based on dynamic threshold voltage transistors (DTMOS) for low-voltage, low-power and low-noise operational amplifier has been described. Its input differential pair is based on the combination of DTMOS and composite transistors (self-cascode transistors). Under 1V supply voltage, input stages for operational amplifier that input differential pairs operate in three different modes (improved DTMOS, conventional DTMOS and BTMOS) using standard 0.18mum CMOS technology has been simulated by HSPICE. The results show the DC gain of proposed input stage increases about 6dB compared with that based on conventional DTMOS. Moreover, the proposed input stage still remains low noise. It should be also noted that it doesn´t worsen other performances, such as input common-mode range, area and power. Thus, it has a high degree of freedom in low-voltage low-noise circuit design