Low-voltage and high-speed flipped voltage follower using DTMOS transistor

Abstract

In the past body terminal was considered as an exclusive source of unwanted second order effects. But recently use of body terminal is becoming an attractive opportunity for improving the performance of analog integrated circuits. Low frequency harmonic distortion stems from the body effect and is dependent on body effect coefficient. In most of the analysis, body effect present in conventional flipped voltage follower (FVF) has been neglected however in submicron low voltage circuits it cannot be neglected. In this paper, we propose to utilize body effect positively using dynamic threshold MOS (DTMOS) transistor. The proposed FVF exhibits linear behaviour for large excursions of the output voltage and linear range has increased by ±20 mV. There is an improvement in the slew-rate(SR) performance and SR has become more symmetrical in proposed FVF. The proposed FVF is mapped on to the TSMC 250nm CMOS technology. Simulations at low supply voltage of 1.3V validate the proposed FVF. The proposed FVF is expected to be useful in low voltage high speed analog signal processing applications.