Flipped-around multiply-by-two amplifier with unity feedback factor

• DOI: 10.1007/s10470-011-9642-5
• Publication Date: 2011-04-30T13:05:56Z
• Authors: M. Figueiredo; E. Santin; J. Goes; N. Paulino; F. A. P. Barúqui; A. Petraglia
• Keywords: Positive feedback; Negative feedback amplifier; Linearity; Negative feedback

This letter describes a multiply-by-two amplifier inherently insensitive to capacitor mismatch with an enhanced feedback factor of approximately unity. The proposed flipped-around structure, which operates in a single clock cycle, is based on the series association of two charged capacitors to achieve an accurate gain of two. Due to the series association of the capacitors, a nearly unity feedback factor is achieved, greatly enhancing the energy efficiency of the circuit. Simulations, in a standard 0.13 μm 1.2 V CMOS technology, also show a fourfold linearity improvement over the conventional structure.