A 0.3-V High Linear Rail-to-Rail Bulk-Driven OTA in 0.13 μm CMOS

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
$\mu \text{m}$
CMOS process, and supplied with
$\text{V}_{\mathrm{ DD}}$
of 0.3 V, the circuit provides rail to rail input range with THD below 0.5 % for a nominal transconductance of 2.93
$\mu \text{S}$
. The transconductance can be tuned from 1.41
$\mu \text{S}$
to 5.72
$\mu \text{S}$
, with rail-to-rail input swing and THD below 1%. Thanks to its compact structure, the circuit occupies only
$935~\mu \text{m}^{2}$
, with transconductance/power ratio of 5.75
$\mu \text{S}/\mu \text{W}$
.