A 0.3-V High Linear Rail-to-Rail Bulk-Driven OTA in 0.13 μm CMOS
Tomasz Kulej, Fabian Khateb, Daniel Arbet, Viera Stopjaková
Abstract
A new solution for an ultra-low-voltage (ULV), linear operational transconductance amplifier (OTA) is presented in this brief. The circuit is based on a non-tailed, classAB differential stage, combined with an additional linear resistor, which suppress the third-order harmonic term component, thus providing a highly linear DC transfer characteristic with no extra power consumption. While fabricated in a 0.13 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> CMOS process, and supplied with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{V}_{\mathrm{ DD}}$ </tex-math></inline-formula> of 0.3 V, the circuit provides rail to rail input range with THD below 0.5 % for a nominal transconductance of 2.93 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{S}$ </tex-math></inline-formula> . The transconductance can be tuned from 1.41 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{S}$ </tex-math></inline-formula> to 5.72 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{S}$ </tex-math></inline-formula> , with rail-to-rail input swing and THD below 1%. Thanks to its compact structure, the circuit occupies only <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$935~\mu \text{m}^{2}$ </tex-math></inline-formula> , with transconductance/power ratio of 5.75 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{S}/\mu \text{W}$ </tex-math></inline-formula> .